• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.535-538
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• 2009

모바일 단말기 사용자 수의 증가와 위치기반 서비스 기술의 발달로 위치 정보를 활용한 다양한 위치 정보 서비스가 등장하고 있다. 친구들과 약속을 정하는 일은 빈번하게 일어난다. 약속을 정하기 위해서는 모든 친구에게 연락을 해야 하고 각자 선호하는 장소가 다르기 때문에 모든 친구들이 만족할 만한 최적의 장소를 찾기가 어렵다. 본 논문에서는 모바일 환경에서 친구의 위치를 파악하고 사용자와 친구의 성향을 파악하기 위해 협업 필터링과 인구통계학적 정보를 사용하였고, 약속 장소를 선정하기 위해 사용자와 친구의 위치를 기반으로 후보 영역을 선택하여 약속 장소와 시간을 추천하는 서비스를 제공함으로써 약속을 맺기 위한 절차를 간소화 할 뿐 아니라 사용자와 친구의 성향에 맞는 약속 장소를 추천하여 사용자와 친구가 만족 할 수 있는 약속을 형성할 수 있도록 하는 약속 장소, 시간 추천 서비스 시스템을 설계하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.545-548
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• 2008

본 논문은 지도정보를 이용하여 옥내측위 결과를 보정하는 방법을 제안한다. 다양한 옥내측위 관련 연구 결과가 소개되었으나, 지금까지 발표되고 진행되는 연구는 측위의 정확도를 제고하는 방안에 중점을 두고 있다. 그러나 정확도를 아무리 제고하여도 오차를 완전히 제거하기는 불가능하다. 따라서 본 연구는 지도정보를 이용하여 옥내측위 결과를 보정하는 방법을 제안하는 것이다. GPS로 예측한 자동차 궤적을 보정하는 방법으로 map-matching 방법이 널리 연구되었다. 제안하는 방법은 두 선분이 교차하는지 검사하는 함수를 이용하여, 이동단말기가 장애물을 통과하여 움직이는 상황을 나타내는 측위 결과를 실시간으로 즉시 보정한다는 점에서 map-matching 방법과 다르다. 제안하는 실시간 보정 방법은 기존의 map-matching 방법과 함께 측위의 정확도를 제고하기 위하여 사용될 수 있다.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.271-282
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• 2015

In the business environment BYOD(Bring Your Own Device) is used and being expanded continuously. According to a survey conducted by Cisco in 2012 on 600 companies, 95% of them are already permitting the use of BYOD in their work environments so that productivity of their employees has improved as a result. Gartner predicted that the use of BYOD will be caused new security threat. They also suggested to introduce NAC(Network Access Control) to resolve this threat, to separate network zone based on importance of their business, to establish the policy to consider user authority and device type, and to enforce the policy. The purpose of this paper is to design and implement the NAC for granular access control based on IEEE(Institute of Electrical and Electronics Engineers) 802.1X and DHCP(Dynamic Host Configuration Protocol) fingerprinting, and to analyze the performance on BYOD environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.127-132
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• 2014

In this paper, we propose a digital signage method that can control the contents of the screen and download the desired files to individual smart terminal with no touch of digital signage screen by using Kinect. The main features and contributions of the proposed method are as follows. First, can solve the problems such as the risk of bacterial infection, not cleanliness on the screen as well as maximize advertising effectiveness. Second, can support bi-directional communications with computer while we touch only wanted advertisements. The performance evaluation shows the effectiveness of the proposed method. Especially, we can see that the proposed system operates through the recognition of user's actions when the cursor is within the scope of a certain coordinate and the file transfer time to download information is different depending on the PC performance and the version of personal smart device.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.355-359
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• 2009

When an unexpected software exception arises, we programmers are to analyze what causes it. Precisely speaking, we need to analyze the cause and property of the unexpected exception. But if exceptions arise irregularly from unknown causes, it is even more difficult for us to handle them, especially in embedded system like mobile phone software development. In this paper, we propose a debugger-friendly analyzing method for exceptions using aspect oriented programming technique. What we need to know upon arising exceptions is the function call history in order to identify the reason for the exceptions. Since programmers used to spend their debugging time on unidentified exceptions, which arise irregularly our method would greatly improve the embedded software development productivity.

• Journal of IKEEE
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• v.14 no.3
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• pp.224-231
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• 2010

Automatic detection of objects in images has been one of core challenges in the areas such as computer vision and pattern analysis. Especially, with the recent deployment of personal mobile devices such as smart phone, such technology is required to be transported to them. Usually, these smart phone users are equipped with devices such as camera, GPS, and gyroscope and provide various services through user-friendly interface. However, the smart phones fail to give excellent performance due to limited system resources. In this paper, we propose a new scheme to improve object recognition performance based on pre-computation and simple local features. In the pre-processing, we first find several representative parts from similar type objects and classify them. In addition, we extract features from each classified part and train them using regression functions. For a given query image, we first find candidate representative parts and compare them with trained information to recognize objects. Through experiments, we have shown that our proposed scheme can achieve resonable performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.95-102
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• 2006

In this paper, we present the performance analysis and design of a multi-path searcher operating over Rayleigh fading channels when multiple transmit antennas are employed in the down-link of W-CDMA system. The simulation results for the receiver operating characteristics (ROC) for 1, 2, and 4 transmit antennas are presented to corroborate the theoretical analyses. We also propose a procedure to find the optimum parameters of double-dwell serial searcher according to the number of the multiple transmit antennas. Our analyses and simulations indicate that post-detection integration is not necessary when the number of transmit antennas is more than two. Finally, we found that increasing transmit diversity order does not necessarily improve the detection performance when the received pilot signal strength is relatively low. Therefore, this gives us a practical criterion on increasing transmit diversity order.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.802-816
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• 2010

To create gesture from a new text input is an important problem in computer games and virtual reality. Recently, there is increasing interest in gesture stylization to imitate the gestures of celebrities, such as announcer. However, no attempt has been made so far to stylize a gestures using emotion such as happiness and sadness. Previous researches have not focused on real-time algorithm. In this paper, we present a system to automatically make gesture animation from SMS text and stylize the gesture from emotion. A key feature of this system is a real-time algorithm to combine gestures with emotion. Because the system's platform is a mobile phone, we distribute much works on the server and client. Therefore, the system guarantees real-time performance of 15 or more frames per second. At first, we extract words to express feelings and its corresponding gesture from Disney video and model the gesture statistically. And then, we introduce the theory of Laban Movement Analysis to combine gesture and emotion. In order to evaluate our system, we analyze user survey responses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.557-560
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• 2013

MANTET(Mobile Ad-Hoc Networks), which is configured and operated by each terminals with no support of communication infra-structures, is recently expanded its application fields from terrestrial communications to underwater environments with technical advances of Wi/Fi and minimized portable terminals. Underwater sensor network, undersea environment explorations and probes, information transmission for underwater area, etc., is typical application fields of underwater MANET. Especially, Performance measurement and analysis on this application fields is one of important research area and base of design, implementation and operation for underwater MANET. However, the research results are focued on various transmission parameters on network level, and its objects of analysis are also performance of network level. In this paper, transmission performances for application levels are measured and analyzed for user levels on underwater MANET. In this study, voice traffic is assumed as object application traffic, computer simulation which is based on NS-2 having additional implemented functions for underwater communications is used. on some defined scale of MANET, transmission performances according to varying traffic environments are measured and analyzed, operation conditions on underwater MANET is suggested with the analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.796-801
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• 2002

CL1(closed loop mode 1) is one of the closed loop transmit diversity schemes defined by 3GPP WCDMA and adjusts the relative phases of the transmitted signals at the two transmit antennas, thereby maximizing the power of the received signal at the user equipment. A key component of this scheme is to encode the phase difference between two received signals arrived at the user equipment via two different transmit antennas and to send it back to the base station. This paper proposes a new phase difference representation based on the adaptive delta modulation and compares its performance with the corresponding one of CL1. Computer simulations show that, in a slowly fading environment, the proposed scheme produces more realistic representation of the phase difference than the on of the CL1, resulting in a lower BER.