Ask A Girl: Overcoming Peer Pressure - BodiMojo

Peer pressure:?A term we hear about from teachers, parents, friends, siblings, anyone and everyone that?s been encouraged, at some point in their life, to change their attitudes, behaviors, and values in order to fit into certain norms. It?s a struggle we all face at different times for a number of reasons. Peer pressure can come in a variety of forms, and can sometimes influence us when we don?t even recognize it.

Unfortunately, peer pressure begins when we are young and continues to follows us through adolescence and adulthood. It?s one of those things we fall into without even meaning to. Did you ever throw away the healthy lunch your mom packed you in elementary school because all the other kids were doing it? Did you not do your homework just to be ?cool?? Did your favorite color ever change from blue to pink because your friends said blue wasn?t a ?girl? color? These are all subtle forms for peer pressure that you may have experienced as young as six years old.

Conforming in these innocent ways does not affect us as much as the harmful kinds of peer pressure that start occurring in middle school. Adolescence is a stage in our lives when a lot of us pick up habits and behaviors that remain with us for many years. These types of peer pressure are centered on things like alcohol, drugs, cigarettes, eating disorders, and shoplifting; things that teens believe make them popular, attractive, and mature. Girls often engage in eating disorders like purging and starving themselves in order to be skinny and feel attractive to boys. This type of behavior stems from the pressures in the media that center on body image, physical attractiveness, and male dominance.

In general, teens are also surrounded with the idea that their parents are annoying and their friends are cool. Many of us go to our peers for advice about our bodies, our relationships with boys, friends, and family, and what decisions we should make each day. We typically act the same ways our friends act, whether it means eating the same foods, having the same hobbies, having similar attitudes and behaviors, or making certain decisions. The bottom line: our friends affect our actions and our decisions. We can be affected in positive ways or negative ways, depending on who we choose to hang out with and if we choose to conform or to be an individual.

As an adolescent I was significantly influenced by my peers and the things they chose to engage in. In middle school I started to avoid my parents and my sister to hang out with my friends as much as possible. I was easily annoyed with anything my family said to me and I acted as if I was better than all of them. I became captivated with being popular, hanging out with friends, and having boyfriends. I had few hobbies and never really took the time to appreciate anything I had in my life. My attachment to my friends held me back from being an individual and figuring out my talents, hobbies, and personal interests. I became preoccupied with the insignificant things like birthday parties, school dances, flirting, shopping, football games, hanging out downtown, eating junk food and chatting on the computer.

Unfortunately, my conformity and ignorance continued into high school. I continued to spend most of my time with my friends, which is where I inadvertently picked up unhealthy eating habits, laziness, experimentation with alcohol and cigarettes, and a lack of respect for myself. Peer pressure took over my life and I didn?t even know it. I thought this was who I was as a person, and who I would continue to be throughout my life, but I was wrong.

Today I am a happy, healthy, self-confident individual. I have learned to accept and appreciate myself, my body, my family, my education, my health, my friends, and most importantly, my ability to make my own decisions. I want to advocate to everyone experiencing the burdens of peer pressure: do not feel compelled to do or not do anything that makes you uncomfortable. Do not act in any particular way because you think you?re supposed to, and do not pretend to have certain beliefs that are not what you truly think is right. Be your own person and feel proud of yourself every day. It is better to make a decision that brings happiness to you rather than to others. I always say to myself ?those who matter don?t mind and those who mind don?t matter? because it reminds me of the special people I have in my life today. Appreciate and respect yourself, and make sure to always surround yourself with people who do the same.

Similarly Awesome Articles:

  1. Overcoming the Stigma of Summer School
  2. Ask A Girl: How to Deal with Homesickness
  3. Ask A Girl: How it Feels to Be Overweight
  4. Ask a Girl: How to Make the College Process Painless

Source: http://www.bodimojo.com/blog/ask-a-girl-overcoming-peer-pressure/

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Daniel Ricciardo thinks he has competitive edge over Jean-Eric ...

Daniel Ricciardo thinks he has competitive edge over Jean-Eric Vergne ? Formula 1 news

Toro Rosso driver Daniel Ricciardo thinks he has a competitive edge over his teammate, Jean-Eric Vergne since this year?s summer break.

Ricciardo said that he has considerably improved his qualifying pace and has performed quite convincingly in the last few races. Moreover, he said that he has learned a lot from his mistakes in the season so far which has really helped him in getting back in action.

Besides, after securing tenth place finish in the Abu Dhabi Grand Prix, he believes that he has an advantage over Vergne in his team.

?I think definitely the Saturdays have been my stronger point,? Ricciardo said. ?I think in terms of Sundays I gave a few away earlier in the year, I made a few little mistakes and it took me a little bit of time to get what I wanted out of a Sunday. But I think definitely now since the Summer break it's been more in my favour.?

In addition, he said that he has remained positive despite facing difficulties during the opening few races and has tried his best to keep on making the significant improvements in his pace so as to secure good results for his team.

?It's been positive from my side, I think the progression has been positive; the Saturdays have remained strong yet the Sundays have improved, which were my weaker point at the beginning of the year,? he added.

Furthermore, he said that he is looking forward to deliver his best in the remaining two races of the ongoing season.

Even though, both the drivers have secured their race seats in their team for the coming year. However, the better one may get a chance to drive Red Bull in the future.

Red Bull Racing team principal, Christian Horner has said that they are keeping an eye on the performance of Ricciardo and Vergne to assess that who has the potential to secure a race seat in their team.

It will be very interesting to see how the drivers of the Faenza based team perform in the remaining two grands prix of the current season.?

Source: http://blogs.bettor.com/Daniel-Ricciardo-thinks-he-has-competitive-edge-over-Jean-Eric-Vergne-Formula-1-news-a199640

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Iraq signs oil deal with Russian-led group

BAGHDAD (AP) ? Iraq's Oil Ministry says it has finalized a deal with a consortium led by Russian oil giant Bashneft to search for oil in the country's south.

Ministry spokesman Assem Jihad says Bashneft and its UK partner Premier will explore the 8,000-square-kilometer (3,100-square-mile) Block 12 , shared by the provinces of Muthana and Najaf. They will be paid US$5 for each barrel of oil equivalent.

Thursday's signing ceremony took place at the Oil Ministry in Baghdad. The contract is one of four deals Iraq awarded in its latest bidding round to hunt for oil and gas.

Iraq, which sits atop of 143.1 billion barrels of proven oil reserves and 126.7 trillion cubic feet of natural gas, is seeking to develop its vast resources after decades of war, U.N. sanctions and neglect.

Source: http://news.yahoo.com/iraq-signs-oil-deal-russian-led-group-120000405--finance.html

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Is It Illegal To Instagram Your Vote?

This may sound familiar: a friend of yours posts a picture of her completed ballot, shot moments ago, inside a New York City voting booth. Was it legal to take that photo to begin with? In a surprising number of states, this simple act—one you've no doubt seen repeated on Instagram and Facebook dozens of times today—would've constituted a misdemeanor. More »

Source: http://feeds.gawker.com/~r/gizmodo/full/~3/Vgv2EhO8rvs/is-it-illegal-to-instagram-your-vote

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Greek unions target austerity skeptics

A woman with her luggage stands under the sign of Greece's Railway Organization at the central train station during a 48-hour nationwide general strike in Athens on Tuesday, Nov. 6, 2012. Greece's unions are holding their third general strike in six weeks in the hope of persuading politicians not to back a major new austerity program that will commit the country to further hardship. (AP Photo/Thanassis Stavrakis)

A woman with her luggage stands under the sign of Greece's Railway Organization at the central train station during a 48-hour nationwide general strike in Athens on Tuesday, Nov. 6, 2012. Greece's unions are holding their third general strike in six weeks in the hope of persuading politicians not to back a major new austerity program that will commit the country to further hardship. (AP Photo/Thanassis Stavrakis)

A cleaning woman is seen on the empty platform of the Athens central train station during a 48-hour nationwide general strike on Tuesday, Nov. 6, 2012. Greece's unions are holding their third general strike in six weeks in the hope of persuading politicians not to back a major new austerity program that will commit the country to further hardship. (AP Photo/Thanassis Stavrakis)

(AP) ? Greece was hit by its third general strike in six weeks Tuesday, as its trade union hope to persuade politicians to reject a major new austerity program that will condemn the country to more years of hardship in exchange for continued bailout funding.

Flights to and from the country stopped at 10:00 a.m. (0800GMT) at the start of a 48-hour strike that has closed schools, halted train and ferry services, and kept hospitals running on emergency staff only.

Two days of demonstrations are planned to start after 11:00 a.m. (0900GMT) Tuesday, continuing until lawmakers vote late Wednesday on the bill to slash ?13.5 billion ($17.3 billion) from budget spending over the next two years.

Conservative Prime Minister Antonis Samaras is facing his first serious crisis since he formed the coalition government in June as Socialist and left-wing members lawmakers threaten to vote against the austerity package.

The deeply unpopular measures include new deep pension cuts and tax hikes, a two-year increase in the retirement age to 67, and laws that will make it easier to fire and transfer civil servants. The country is suffering in a deep recession set to enter a sixth year, and record high unemployment of 25 percent.

If Parliament rejects the package, Greece will lose access to the rescue loans from the European Union and International Monetary Fund that have kept it afloat since May 2010.

The country would then run out of money ? as soon as by Nov. 16, according to Samaras ? default on its debts and, most likely, abandon the 17-member eurozone. The ensuing hyperinflation and currency depreciation would intensify domestic misery.

The international repercussions would also be severe, amid fears that other troubled eurozone members could follow Greece's lead.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/cae69a7523db45408eeb2b3a98c0c9c5/Article_2012-11-06-Greece-Financial%20Crisis/id-d06d0f3b3a2b4028b0ca25c56a4ae0f0

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The Advantage Of Getting Anti-virus Firewall Software Program And ...

You are here: Home / General / The Advantage Of Getting Anti-virus Firewall Software Program And Web Safety Software In Your Personal

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When you?re choosing anti-virus world broad internet safety pc software for your personal computer, do not forget to check the minimum system requirements provided by the manufacturer so that you will have an concept if the software plan will be compatible to the body and will not set off it to slow down.

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Source: http://www.theyellowads.com/computers_technology/the-advantage-of-getting-anti-virus-firewall-software-program-and-web-safety-software-in-your-personal/

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Kentucky fires football coach Joker Phillips

Kentucky head coach Joker Phillips stands on the sidelines during the first half of a game against Missouri Saturday, Oct. 27, 2012, in Columbia, Mo.

ASSOCIATED PRESS

The Associated Press

Published: Sunday, November 4, 2012 at 4:55 p.m.
Last Modified: Sunday, November 4, 2012 at 4:55 p.m.

LEXINGTON, Ky. ? Kentucky has fired football coach Joker Phillips, a day after an embarrassing loss to Vanderbilt.

Athletic Director Mitch Barnhart announced Phillips? dismissal Sunday in an open letter on the athletic department?s web site.

The Wildcats lost their eighth straight game on Saturday, a 40-0 home loss to Vanderbilt. It was their worst loss to the Commodores in 96 years.

The 49-year-old Phillips is 12-23 overall in three seasons at Kentucky. He will finish this season.

Barnhart says the school will begin a nationwide search for a new coach immediately.

The Wildcats (1-9, 0-7 Southeastern Conference) went to a bowl game two years ago but have gotten worse each season since. Kentucky is off this week, and then closes the season with games against Samford and Tennessee.

Source: http://www.heraldtribune.com/article/20121104/wire/121109818

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Radiohead: Electioneering

Later tonight, we'll be finished with the 2012 election. Finally and thank god. We're all probably feeling a little cynical right now, which makes Radiohead's Electioneering particularly relevant. More »

Source: http://feeds.gawker.com/~r/gizmodo/full/~3/BIM_UTmKMqE/radiohead-electioneering

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PST: Juventus' strange, remarkable run

Juventus went 49 Serie A games without a loss, but when they finally fell 3-1 to Internazionale yesterday, the reaction was less shock than confirmation, the feeling that an inevitability had come. Inter were clearly the better side ? an advantage they needed after a wrongly allowed goal put them down one after 18 seconds ? though they weren?t the first team to outplay Juventus over the league 18 months. That they were the first to beat them in league made the preceding 49 games all the more confusing.

?We came back out for the second-half with so much anger after the offside goal,?1 Inter striker Diego Milito admitted afterward, the Argentine having taken his customary place in the big stage?s spotlight. His two goals had Inter up in by the 75th minute, with Rodrigo Palacio?s late insurance handing Juve their first loss at Juventus Stadium.

?We are still proud of these lads, who didn?t lose for 49 games,? Juve general manager Guiseppe Marotta said. [N]ow we must look forward.?2

?The Nerazzurri will compete at the top right until the end. We accept this defeat and we?re not going to make any bones about it.

For some, it was a surprising moment of humility. In the days before the game, Marotta made the mistake of publicly chiding Inter?s preparation, his glib derision catching the Nerazzurri?s attention.

?I was annoyed by what Mr. Marotta said before the game,? Inter coach Andrea Stramaccioni conceded after ending Juve?s run. ?He made a sarcastic remark about our blithe approach. We work hard and you could see that.?3

The team?s formation symbolized that preparation. Stramaccioni took advantage of Juve?s two-forward approach by going three at the back, an approach they?ve used a various times this season, the team using both 3-4-3 and 4-3-3 formations. Surprisingly, Stramaccioni chose the more audacious approach on Saturday, Inter?s 3-4-3 seeking to pressure Juve high while taking advantage of the Old Lady?s lack of a top finisher.

Though Inter relinquished their clean sheet early, Juventus was held at bay for the next 90 minutes, a testament to both the Nerazzurri?s preparations and Juve?s lack of punch.

?We weren?t used to losing anymore, even if we played well,?4 captain Gianluigi Buffon said after the game, Juventus conceding three goals in league for the first time since last November. eventually noting another issue with Juve?s attitude. They?d never conceded three in their new home.

Buffon went on to note another issue which, like Marotta?s ill-advised criticisms, hints Juve took Inter for granted.

?I did not like our attitude after we went 1-0 up. I don?t understand why we sat there waiting for them outside our own box, we were far too carefree.?

Passivity is not a new problem for Juventus, a team whose 49-match winning streak defied their approach. This year?s Champions League has highlighted the problem, the Old Lady sitting on a disappointing three points after as many matches. The team too often relies on opportunism in lieu of control, and while their streak shows the approach can be successful, it frequently leaves your success in the hands of your opponents.

The approach also leaves the team content to sit on a lead, an attitude that would have been difficult to maintain last year had Inter, Milan, and Napoli (thanks to their Champions League commitment) not all, simultaneously taken a step back. Udinese had sold Alexis Sanchez. Fiorentina was in disarray. As with all remarkable results, Juve?s streak required remarkable circumstances.

?In my view, we could?ve dealt with the game differently,? Buffon continued, ?but after 15 minutes we just left the initiative to them.?

?Was our attack light,? Moratta asked, rhetorically, after the game. ?Yes, maybe with a more clinical striker we might?ve had a different result.?5

The remark understates the difference between the sides. With better finishing, Juventus may have scored another goal, but they still wouldn?t have had an answer for Milito.

Coming into the game, Inter?s focal point had 113 goals in his 191 Serie A appearances, yet he?d never scored from open play against Juventus. He?d converted from the spot during his time with Genoa, and in the 59th minute, Milito did the same on Saturday, equalizing after a penalty on Claudio Marchisio.

Sixteen minutes later, Milito finally had his open play goal, putting home a rebound of a Fredy Guarin blast to give Inter the lead. With Palacio?s late goal, Inter had their 3-1 win, giving Andrea Stramaccioni the biggest victory of his young career.

?Is this the best day of my career? The best day of my career was when the president chose me to coach Inter,? the 36-year-old modestly explained after the victory, preferring to keep the focus on the club rather than himself. ?I?m proud to be the Inter coach and I?m happy for our fans who can enjoy this win.?6

Stramaccioni?s appointment was almost a last resort in spring, with Inter having already gone through two coaches after Leonardo?s departure to Paris Saint-Germain. Gian Piero Gamsperini was dismissed almost immediately after the 2011-12 season started. Claudio Ranieri failed to engineer the same turnout he?d brought to Roma. When he was dismissed in March, Stramaccioni was promoted from the team?s Primavera side, becoming Inter?s fifth coach since Jos? Mourinho left after the team?s 2010-11 league, cup, Europe triumph.

?Stramaccioni doesn?t need to be compared to Mourinho,? Inter president Massimo Moratti explained. ?He?s just good. He?s surprising.?7

The surprises mean Inter has adjusted their goals.

?I?m happy because what seemed to be a transition season is now starting to look interesting,? Moratti said, with caution. ?[Let's] wait a bit before talking up our title challenge.?

Moratti doesn?t have a choice. Eleven rounds into the season, Inter sits second, one point back of Juventus. After a win in Turin, the Italian press is sure to see Inter as a contender, and with good cause. On talent, they have the means to compete with Juventus and Napoli. If Stramaccioni proves to have move tricks up his sleeve, Inter is as capable of claiming the Scudetto as the league?s other two title hopefuls.

It?s an assessment that only underscores the strange nature of Juventus?s streak. One loss after a 49-game unbeaten run would normally be seen as a blip. Not so in this case. While that feeling could come from the strength of their opponents or the sense that all good things must come to an end, it?s more likely a reflects a more general feeling about Juve?s quality. Though their title earned them respect, there was always wonder at how a team could go from out of Europe to unbeatable ? from redesign to reign in one summer.

That wonder was a euphemistic one. Nobody felt Juventus unbeatable, an attitude reflected in how Napoli beat them in last year?s Coppa Italia final. Inter was similarly aggressive on Saturday, and in doing so, they may have affirmed a blueprint for dealing with the Bianconeri.

Mid-way through last season, Napoli was similarly found out, Juventus helping to uncover an antidote Walter Mazzarri?s 3-5-2. Now it?s Juve?s turn to adapt, even if their adjustment will be more mental than tactical. Though Stramaccioni?s innovations trickled into his formation, the real epiphany in attidute. Like Napoli in the Coppa final, Inter proved you can go after Juventus.



1 ? http://www.goal.com/en-us/news/86/italy/2012/11/04/3502194/milito-anger-at-offside-goal-motivated-inter-comeback
2 ? http://www.espnstar.com/football/serie-a/news/detail/item885085/Inter-driven-by-Marotta-comments/
3 ? http://english.gazzetta.it/Football/03-11-2012/strama-a-sign-of-our-strength-now-juve-should-show-us-respect-913112705397.shtml
4 ? http://www.football-italia.net/26879/buffon-slams-juve-attitude
5 ? http://www.soccerway.com/news/2012/November/04/marotta-rues-lack-of-marksman/
6 ? http://www.espnstar.com/football/serie-a/news/detail/item884902/Moratti:-Stramaccioni-is-just-good/
7 ? http://www.espnstar.com/football/serie-a/news/detail/item884902/Moratti:-Stramaccioni-is-just-good/

Source: http://prosoccertalk.nbcsports.com/2012/11/04/juventus-loses-inter-milan-49-match-unbeaten-run-serie-a/related/

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Innovation: Getting Along | GPS World

By Dorota A. Grejner-Brzezinska, J.N. (Nikki) Markiel, Charles K. Toth and Andrew Zaydak

Innovation Insights with Richard Langley

Richard Langley

COLLABORATION,? n. /k??l?b??re???n/, n. of action. United labour, co-operation; esp. in literary, artistic, or scientific work ? according to the Oxford English Dictionary. Collaboration is something we all practice, knowingly or unknowingly, even in our everyday lives. It generally results in a more productive outcome than acting individually. In scientific and engineering circles, collaboration in research is extremely common with most published papers having multiple authors, for example.

The term collaboration can be applied not only to the endeavors of human beings or other living creatures but also to inanimate objects, too. Researchers have developed systems of miniaturized robots and unmanned vehicles that operate collaboratively to complete a task. These platforms must navigate as part of their functions and this navigation can often be made more continuous and accurate if each individual platform navigates collaboratively in the group rather than autonomously. This is typically achieved by exchanging sensor measurements by some kind of short-range wireless technology such as Wi-Fi, ultra-wide band, or ZigBee, a suite of communication protocols for small, low-power digital radios based on an Institute of Electrical and Electronics Engineers? standard for personal area networks.

A wide variety of navigation sensors can be implemented for collaborative navigation depending on whether the system is designed by outdoor use, for use inside buildings, or for operations in a wide variety of environments. In addition to GPS and other global navigation satellite systems, inertial measurement units, terrestrial radio-based navigation systems, laser and acoustic ranging, and image-based systems can be used.

In this month?s article, a team of researchers at The Ohio State University discusses a system under development for collaborative navigation in transitional environments ? environments in which GPS alone is insufficient for continuous and accurate navigation. Their prototype system involves a land-based deployment vehicle and a human operator carrying a personal navigator sensor assembly, which initially navigate together before the personal navigator transitions to an indoor environment. This system will have multiple applications including helping first responders to emergencies. Read on.

?Innovation? is a regular feature that discusses advances in GPS technology andits applications as well as the fundamentals of GPS positioning. The column is coordinated by Richard Langley of the Department of Geodesy and Geomatics Engineering, University of New Brunswick. He welcomes comments and topic ideas. To contact him, see the ?Contributing Editors? section on page 6.


Collaborative navigation is an emerging field where a group of users navigates together by exchanging navigation and inter-user ranging information. This concept has been considered a viable alternative for GPS-challenged environments. However, most of the developed systems and approaches are based on fixed types and numbers of sensors per user or platform (restricted in sensor configuration) that eventually leads to a limitation in navigation capability, particularly in mixed or transition environments.

As an example of an applicable scenario, consider an emergency crew navigating initially in a deployment vehicle, and, when subsequently dispatched, continuing in collaborative mode, referring to the navigation solution of the other users and vehicles. This approach is designed to assure continuous navigation solution of distributed agents in transition environments, such as moving between open areas, partially obstructed areas, and indoors when different types of users need to maintain high-accuracy navigation capability in relative and absolute terms.

At The Ohio State University (OSU), we have developed systems that use multiple sensors and communications technologies to investigate, experimentally, the viability and performance attributes of such collaborative navigation. For our experiments, two platforms, a land-based deployment vehicle and a human operator carrying a personal navigator (PN) sensor assembly, initially navigate together before the PN transitions to the indoor environment.

In the article, we describe the concept of collaborative navigation, briefly describe the systems we have developed and the algorithms used, and report on the results of some of our tests. The focus of the study being reported here is on the environment-to-environment transition and indoor navigation based on 3D sensor imagery, initially in post-processing mode with a plan to transition to real time.

The Concept

Collaborative navigation, also referred to as cooperative navigation or positioning, is a localization technique emerging from the field of wireless sensor networks (WSNs). Typically, the nodes in a WSN can communicate with each other using wireless communications technology based on standards, such as Zigbee/IEEE 802.15.4. The communication signals in a WSN are used to derive the inter-nodal distances across the network. Then, the collaborative navigation solution is formed by integrating the inter-nodal range measurements among nodes (users) in the network using a centralized or decentralized Kalman filter, or a least-squares-based approach.

A paradigm shift from single to multi-sensor to multi-platform navigation is illustrated conceptually in Figure 1. While conventional sensor integration and integrated sensor systems are commonplace in navigation, sensor networks of integrated sensor systems are a relatively new development in navigation. Figure 2 illustrates the concept of collaborative navigation with emphasis on transitions between varying environments. In actual applications, example networks include those formed by soldiers, emergency crews, and formations of robots or unmanned vehicles, with the primary objective of achieving a sustained level of sufficient navigation accuracy in GPS-denied environments and assuring seamless transition among sensors, platforms, and environments.

Figure 1. Paradigm shift in sensor integration concept for navigation.

Figure 2. Collaborative navigation and transition between varying environments.

Field Experiments and Methodology

A series of field experiments were carried out in the fall of 2011 at The Ohio State University (OSU), and in the spring of 2012 at the Nottingham Geospatial Institute of the University of Nottingham, using the updated prototype of the personal navigator developed earlier at the OSU Satellite Positioning and Inertial Navigation Laboratory, and land-based multisensory vehicles. Note that the PN prototype is not a miniaturized system, but rather a sensor assembly put together using commercial off-the-shelf components for demonstration purposes only.

The GPSVan (see Figure 3), the OSU mobile research navigation and mapping platform, and the recently upgraded OSU PN prototype (see Figure 4) jointly performed a variety of maneuvers, collecting data from multiple GPS receivers, inertial measurement units (IMUs), imaging sensors, and other devices. Parts of the collected data sets have been used for demonstrating the performance of navigation indoors and in the transition between environments, and it is this aspect of our experiments that will be discussed in the present article.

Figure 3. Land vehicle, OSU GPSVan.

Figure 4. Personal navigator sensor assembly.

The GPSVan was equipped with navigation, tactical, and microelectromechanical systems (MEMS)-grade IMUs, installed in a two-level rigid metal cage, and the signals from two GPS antennas, mounted on the roof, were shared among multiple geodetic-grade dual-frequency GPS receivers. In addition, odometer data were logged, and optical imagery was acquired in some of the tests.

The first PN prototype system, developed in 2006?2007, used GPS, IMU, a digital barometer, a magnetometer compass, a human locomotion model, and 3D active imaging sensor, Flash LIDAR (an imaging light detection and ranging system using rapid laser pulses for subject illumination). Recently, the design was upgraded to include 2D/3D imaging sensors to provide better position and attitude estimates indoors, and to facilitate transition between outdoor and indoor environments. Consequently, the current configuration allows for better distance estimation among platforms, both indoors and outdoors, as well as improving the navigation and tracking performance in general.

The test area where data were acquired to support this study, shown in Figure 5, includes an open parking lot, moderately vegetated passages, a narrow alley between buildings, and a one-storey building for indoor navigation testing. The three typical scenarios used were:
1)?? ?Sensor/platform calibration: GPSVan and PN are connected and navigate together.
2)?? ?Both platforms moved closely together, that is, the GPSVan followed the PN?s trajectory.
3)?? ?Both platforms moved independently.

Image-Based Navigation

The sensor of interest for the study reported here is an image sensor that actually includes two distinct data streams: a standard intensity image and a 3D ranging image, see Figure 6. The unit consists primarily of a 640 ? 480 pixel array of infrared detectors. The operational range of the sensor is 0.8?10 meters, with a range resolution of 1 centimeter at a 2-meter distance.

Figure 6. PN captured 3D image sequence from inside the building.

In this study, the image-based navigation (no IMU) was considered. To overcome this limitation, the intensity images acquired simultaneously with the range data by the unit were leveraged to provide crucial information. The two intensity images were processed utilizing the Scale Invariant Feature Transform (SIFT) algorithm to identify matching features between the pair of 2D intensity images.

The SIFT algorithm has been primarily applied to 1D and 2D imagery to date; the authors are not aware of any research efforts to apply SIFT to 3D datasets for the expressed purpose of positioning. Analysis at our laboratory supported well-published results regarding the exceptional performance of SIFT with respect to both repeatability and extraction of the feature content. The algorithm is remarkably robust to most image corruption schema, although white noise above 5 percent does appear to be the primary weakness of the algorithm. The algorithm suffers in three critical areas with respect to providing a 3D positioning solution. First, the algorithm is difficult to scale in terms of the number of descriptive points; that is, the algorithm quickly becomes computationally intractable for a large number (>5,000) of pixels. Secondly, the matching process is not unique; it is exceptionally feasible for the algorithm to match a single point in one image to multiple points in another image. Finally, since the algorithm loses spatial positioning capabilities to achieve the repeatability, the ability to utilize matching features for triangulation or trilateration becomes impaired. Owing to the noted issues, SIFT was not found to be a suitable methodology for real-time positioning based on 3D Flash LIDAR datasets.

Despite these drawbacks, the intensity images offer the only available sensor input beyond the 3D ranging image. As such, the SIFT methodology provides what we believe to be a ?best in class? algorithmic approach for matching 2D intensity images. The necessity of leveraging the intensity images will be apparent shortly, as the schema for deriving platform position is explained.

The algorithm has been developed and implemented by the second author (see Further Reading for details). The algorithm utilizes eigenvector ?signatures? for point features as a means to facilitate matching. The algorithm is comprised of four steps:
1)?? ?Segmentation
2)?? ?Coordinate frame transformation
3)?? ?Feature matching
4)?? ?Position and orientation determination.

The algorithm utilizes the eigenvector descriptors to merge points likely to belong to a surface and identify the pixels corresponding to transitions between surfaces. Utilizing an initial coarse estimate from the IMU system, the results from the previous frame are transformed into the current coordinate reference frame by means of a Random Sampling Consensus or RANSAC methodology. Matching of static transitional pixels is accomplished by comparing eigenvector ?signatures? within a constrained search window. Once matching features are identified and determined to be static, the closed form quaternion solution is utilized to derive the position and orientation of the acquisition device, and the result updates the inertial system in the same manner as a GPS receiver within the common GPS/IMU integration. The algorithm is unique in that the threshold mechanisms at each step are derived from the data itself, rather than relying upon a-priori limits. Since the algorithm only utilizes transitional pixels for matching, a significant reduction in dimensionality is generally accomplished and facilitates implementation on larger data frames.

The key point in this overview is the need to provide coarse positioning information to the 3D matching algorithm to constrain the search space for matching eigenvector signatures. Since the IMU data were not available, the matching SIFT features from the intensity images were correlated with the associated range pixel measurements, and these range measurements were utilized in Horn?s Method (see Further Reading) to provide the coarse adjustment between consecutive range image frames. The 3D-range-matching algorithm described above then proceeds normally.

The use of SIFT to provide the initial matching between the images entails the acceptance of several critical issues, beyond the limitations previously discussed. First, since the SIFT algorithm is matching 2D features on the intensity image; there is no guarantee that the matched features represent static elements in the field of view. As an example, SIFT can easily ?match? the logo on a shirt worn by a moving person; since the input data will include the position of non-static elements, the resulting coarse adjustment may possess very large biases (in position). If these biases are significant, constraining the search space may be infeasible, resulting in either the inability to generate eigenvector matches (worst case) or a longer search time (best case). Since the 3D-range-matching algorithm checks the two range images for consistency before the matching process begins, this can be largely mitigated in implementation. Secondly, the SIFT features are located with sub-pixel location, thus the correlation to the range pixel image will inherently possess an error of ? 1 pixel (row and column). The impact of this error is that range pixels utilized to facilitate the coarse adjustment may in fact not be correct; the correct range pixel to be matched may not be the one selected. This will result in larger errors during the initial (coarse) adjustment process. Third, the uncertainty of the coarse adjustment is not known, so a-priori estimates of the error ellipse must be made to establish the eigenvector search space. The size and extent of these error ellipses is not defined on-the-fly by the data, which reduces one of the key elements of the 3D matching algorithm. Fourth, the limited range of the image sensor results in a condition where intensity features have no associated range measurement (the feature is out of range for the range device). This reduces the effective use of SIFT features for coarse alignment. However, using the intensity images does demonstrate the ability of the 3D-range-matching algorithm to generically utilize coarse adjustment information and refine the result to provide a navigation solution.

Data Analysis

In the experiment selected for discussion in this article, initially, the PN was initially riding in the GPSVan. After completing several loops in the parking lot (the upper portion of Figure 5), the PN then departed the vehicle and entered the building (see Figure 7), exited the facility, completed a trajectory around the second building (denoted as ?mixed area? in Figure 5), and then returned to the parking lot.

Figure 7. Building used as part of the test trajectory for indoor and transition environment testing; yellow line: nominal personal navigator indoor trajectories; arrows: direction of personal navigator motion inside the building; insert: reconstructed trajectory section, based on 3D image-based navigation.

While minor GPS outages can occur under the canopy of trees, the critical portion of the trajectory is the portion occurring inside the building since the PN platform will be unable to access the GPS signal during this portion of the trajectory. Our efforts are therefore focused on providing alternative methods for positioning to bridge this critical gap.

Utilizing the combined intensity images (for coarse adjustment via SIFT) and the 3D ranging data, a trajectory was derived for travel inside the building at the OSU Supercomputing Facility. There is a finite interval between exiting the building and recovery of GPS signal lock during which the range acquisition was not available; thus the total extent of travel distance during GPS signal outage is not precisely identical to the travel distance where 3D range solutions were utilized for positioning. We estimate the distance from recovery of GPS signals to the last known 3D ranging-derived position to be approximately 3 meters. Based upon this estimate, the travel distance inside the building should be approximately 53.5 meters (forward), 9.5 meters (right), and 0.75 meters (vertical). Based upon these estimates, the total misclosure based upon 3D range-derived positions is provided in Table 1. The asterisk in the third row indicates the estimated nature of these values.

Table 1. Approximate positional results for the OSU Supercomputing Facility trajectory.

The average positional uncertainty reflects the relative, frame-to-frame error reported by the algorithm during the indoor trajectory. This includes both IMU and 3D ranging solutions. The primary reason for the rather large misclosure in the forward and vertical directions is the result of three distinct issues. First, the image ranging sensor has a limited range; during certain portions of the trajectory the sensor is nearly ?blind? due to lack of measurable features within the range. During this period, the algorithm must default to the IMU data, which is known to be suspect, as previously discussed. Secondly, the correlation between SIFT features and range measurement pixels can induce errors, as discussed above. Third, the 3D range positions and the IMU data were not integrated in this demonstration; the range positions were used to substitute for the lost GPS signals and the IMU was drifting. Resolving this final issue would, at a minimum, reduce the IMU drift error and improve the overall solution.

A follow-up study conducted at a different facility was completed using the same platform and methodology. In this study, a complete traverse was completed indoors forming a ?box? or square trajectory, which returned to the original entrance point. A plot of the trajectory results is provided in Figure 8. The misclosure is less than four meters with respect to both the forward (z) and right (x) directions. While similar issues exist with IMU drift (owing to lack of tight integration with the ranging data), a number of problems between the SIFT feature/range pixel correlation portion of the algorithm are evident; note the large ?clumps? of data points, where the algorithm struggles to reconcile the motions reported by the coarse (SIFT-derived) position and the range-derived position.

Figure 8. Indoor scenario: square (box) trajectory.

Conclusions

As demonstrated in this paper, the determination of position based upon 3D range measurements can be seen to have particular potential benefit for the problem of navigation during periods of operation in GPS-denied environments. The experiment demonstrates several salient points of use in our ongoing research activities. First, the effective measurement range of the sensor is paramount; the trivial (but essential) need to acquire data is critical to success. A major problem was the presence of matching SIFT features but no corresponding range measurement. Second, orientation information is just as critical as position; the lack of this information significantly extended the time required to match features (via eigenvector signatures). Third, there is a critical need for the sensor to scan not only forward (along the trajectory) but also right/left and up/down. Obtaining features in all axes would support efforts to minimize IMU drift, particularly in the vertical. Alternatively, a wider field of view could conceivably accomplish the same objective. Finally, the algorithm was not fully integrated as a substitute for GPS positioning and the IMU was free to drift. Since the 3D ranging algorithm cannot guarantee a solution for all epochs, accurate IMU positioning is critical to bridge these outages. Fully integrating the 3D ranging solution with a GPS/IMU/3D schema would significantly reduce positional errors and misclosure.

Our study indicates that leveraging 3D ranging images to achieve indoor relative (frame-to-frame) positioning shows great promise. The utilization of SIFT to match intensity images was an unfortunate necessity dictated by data availability; the method is technically feasible but our efforts would suggest there are significant drawbacks to this application, both in terms of efficiency and positional accuracy. It would be better to use IMU data with orientation solutions to derive the best possible solution. Our next step is the full integration within the IMU to enable 3D ranging solutions to update the ongoing trajectory, which we believe will reduce the misclosure and provide enhanced solutions supporting autonomous (or semi-autonomous) navigation.

Acknowledgments

This article is based on the paper ?Cooperative Navigation in Transitional Environments,? presented at presented at PLANS 2012, the Institute of Electrical and Electronics Engineers / Institute of Navigation Position, Location and Navigation Symposium held in Myrtle Beach, South Carolina, April 23?26, 2012.

Manufacturers

The equipment used for the experiments discussed in this article included a NovAtel Inc. SPAN system consisting of a NovAtel OEMV GPScard, a Honeywell International Inc. HG1700 Ring Laser Gyro IMU, a Microsoft Xbox Kinect 3D imaging sensor, and a Casio Computer Co., Ltd. Exilim EX-H20G Hybrid-GPS digital camera.


DOROTA GREJNER-BRZEZINSKA is a professor and leads the Satellite Positioning and Inertial Navigation (SPIN) Laboratory at OSU, where she received her M.S. and Ph.D. degrees in geodetic science.

J.N. (NIKKI) MARKIEL is a lead geophysical scientist at the National Geospatial-Intelligence Agency. She obtained her Ph.D. in geodetic engineering at OSU.

CHARLES TOTH is a senior research scientist at OSU?s Center for Mapping. He received a Ph.D. in electrical engineering and geoinformation sciences from the Technical University of Budapest, Hungary.

ANDREW ZAYDAK is a Ph.D. candidate in geodetic engineering at OSU.

FURTHER READING

? The Concept of Collaborative Navigation

?The Network-based Collaborative Navigation for Land Vehicle Applications in GPS-denied Environment? by J-K. Lee, D.A. Grejner-Brzezinska and C. Toth in the Royal Institute of Navigation Journal of Navigation; in press.

?Positioning and Navigation in GPS-challenged Environments: Cooperative Navigation Concept? by D.A. Grejner-Brzezinska, J-K. Lee and C. K. Toth, presented at FIG Working Week 2011, Marrakech, Morocco,? May 18-22, 2011.

?Network-Based Collaborative Navigation for Ground-Based Users in GPS-Challenged Environments? by J-K. Lee, D. Grejner-Brzezinska, and C.K. Toth in Proceedings of ION GNSS 2010, the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation, Portland, Oregon, September 21-24, 2010, pp. 3380-3387.

? Sensors Supporting Collaborative Navigation

?Challenged Positions: Dynamic Sensor Network, Distributed GPS Aperture, and Inter-nodal Ranging Signals? by D.A. Grejner-Brzezinska, C.K. Toth, J. Gupta, L. Lei, and X. Wang in GPS World, Vol. 21, No. 9, September 2010, pp. 35-42.

?Positioning in GPS-challenged Environments: Dynamic Sensor Network with Distributed GPS Aperture and Inter-nodal Ranging Signals? by D.A. Grejner-Brzezinska, C. K. Toth, L. Li, J. Park, X. Wang, H. Sun, I.J. Gupta, K. Huggins and Y. F. Zheng (2009): in Proceedings of ION GNSS 2009, the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation, Savannah, Georgia, September 22-25, 2009, pp. 111?123.

?Separation of Static and Non-Static Features from Three Dimensional Datasets: Supporting Positional Location in GPS Challenged Environments ? An Update? by J.N. Markiel, D. Grejner-Brzezinska, and C. Toth in Proceedings of ION GNSS 2007, the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation, Fort Worth, Texas, September 25-28, 2007, pp. 60-69.

? Personal Navigation

?Personal Navigation: Extending Mobile Mapping Technologies Into Indoor Environments? by D. Grejner-Brzezinska, C. Toth, J. Markiel, and S. Moafipoor in Boletim De Ciencias Geodesicas, Vol. 15, No. 5, 2010, pp. 790-806.

?A Fuzzy Dead Reckoning Algorithm for a Personal Navigator? by S. Moafipoor, D.A. Grejner-Brzezinska, and C.K. Toth, in Navigation, Vol. 55, No. 4, Winter 2008, pp. 241-254.

?Quality Assurance/Quality Control Analysis of Dead Reckoning Parameters in a Personal Navigator? by S. Moafipoor, D. Grejner-Brzezinska, C.K. Toth, and C. Rizos in Location Based Services & TeleCartography II: From Sensor Fusion to Context Models, G. Gartner and K. Rehrl (Eds.), Lecture Notes in Geoinformation & Cartography, Springer-Verlag, Berlin and Heidelberg, 2008, pp. 333-351.

?Pedestrian Tracking and Navigation Using Adaptive Knowledge System Based on Neural Networks and Fuzzy Logic? by S. Moafipoor, D. Grejner-Brzezinska, C.K. Toth, and C. Rizos in Journal of Applied Geodesy, Vol. 1, No. 3, 2008, pp. 111-123.

? Horn?s Method

?Closed-form Solution of Absolute Orientation Using Unit Quaternions? by B.K.P. Horn in Journal of the Optical Society of America, Vol. 4, No. 4, April 1987, p. 629-642.

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