• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.71-82
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• 2011

The RFID system provides undeniable advantages so that it is used for various application. However recent RFID system is vulnerable to some attacks as eavesdropping, replay attack, message hijacking, and tag tampering, because the messages are transmitted through the wireless channel and the tags are cheap. Above attacks cause the tag and reader impersonation, denial of service by invalidating tag, and the location tracking concerning bearer of tags, A lot of RFID authentication protocol bas been proposed to solve the vulnerability. Since Weis, Sanna, Rivest, and Engel, proposed the bash-based RFID authentication protocol, many researchers have improved hash-based authentication protocol and recent bash-based authentication protocols provide security and desirable privacy. However, it remains open problem to reduce the tag identification time as long as privacy and security are still guaranteed. Here we propose a new protocol in which the tags generate the message depending on the state of previous communitions between tag and reader. In consequence, our protocol allows a server to identify a tag in a reasonable amount of time while ensuring security and privacy, To be specific, we reduced the time for the server to identify a tag when the last session finished abnormally by at least 50% compared with other bash-based schemes that ensure levels of security and privacy similar to ours.

• Journal of Industrial Convergence
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• v.21 no.6
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• pp.43-51
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• 2023

This study analyzed the patent status of the outdoor exercise equipment used primarily by the elderly. The purpose is to utilize the basic data obtained to promote the health of the elderly. The information on the patent was collected from KIPRIS, an information search service provided by the Korean Intellectual Property Office. The search term used was 'outdoor exercise equipment', directly related patents were selected, and a final 157 were analyzed. As a result of the analysis, first, patent registration began in 2007, and 2-3 patents were registered on average every year. Second, patents from the perspective of sports convergence that provide an exercise prescription system using wireless communication, such as the ability to generate electricity by operating a power generation module, providing information on the user's exercise amount, or preventing the loss and theft of weights and safety accidents due to their characteristics, were searched for. Lastly, patents related to exercise equipment that can provide user convenience and increase the frequency of use of exercise equipment were searched. The results of this study confirmed that outdoor exercise equipment is being developed more for the elderly and their convenience, and that companies and public institutions are showing increased interest in outdoor exercise equipment for the elderly. In addition to patent trends analysis, follow-up research in connection with exercise programs using outdoor exercise equipment is needed to develop practical and convenient outdoor exercise equipment in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.15-22
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• 2010

Today's rapid shifts toward a new paradigm are combining city spaces with reality and technology, which is known as a ubiquitous environment. An ubiquitous environment means that 'whenever' and 'wherever' become connected. It is a great possibility that this will change our future lifestyle. Korea has the biggest advantage in the implementation of this new environment, such as having an excellent network infrastructure. Using these attributes of a ubiquitous environment, changes are being made toward ubiquitous cities within developing fields of construction, landscaping, streets, art, and the environment. This research is based on background of research that activated media pole in public city space has been done research about reality of digital skill, fusion, and sense of ubitizen, and Kang-Nam U-street applied by ubiquitous technique. While reflecting an environment that can be utilized in a modern digital society, the application of ubiquitous technology to media pole can be a space for the two-way communication of the current paradigm. It would also be meaningful to create a new cultural space through media pole. Through evaluation, citizens of the ubiquitous age are going to interact to raise the satisfaction that media pole in city space can prevent giving direction to develop and trial and error about service ability, identity, and publicity. Finally, the media pole can be used as a fundamental element to suggest directions for change when viewed as future development.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.15-29
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• 2005

Truck Shipment Safety Information, which is a part of the development of NERIS is divided into Optimal Route Guidance System and Emergency Response System. This research is for establishing an advance warning system, which aims for preventing damages(fire, explosion, gas-escape etc.) and detecting incidents that are able to happen during transporting hazardous materials in advance through monitoring the position of moving vehicles and the state of hazardous materials in real-time. This research is peformed to confirm the practical possibility of application of the advance warning system that monitors whether the hazardous materials transport vehicles move the allowed routes, finds the time and the location of incidents of the vehicles promptly and develops the emergency system that is able to respond to the incidents as well by using the technologies of CPS, CDMA and CIS with testing the ability of performance. As the results of the test, communication accuracies are 99$\%$ in freeway, 96$\%$ in arterial, 97$\%$ in hilly sections, 99$\%$ in normal sections, 96$\%$ in local sections, 99$\%$ in urban sections and 98$\%$ in tunnels. According to those results, the system has been recorded a high success rate of communication that enough to apply to the real site. However, the weak point appeared through the testing is that the system has a limitation of communication that is caused in the rural areas and certain areas where are fewer antennas that make communication possible between on-board unit and management server. Consequently, for the practical use of this system, it is essential to develop the exclusive en-board unit for the vehicles and find the method that supplements the receiving limitation of the GPS coordinates inside tunnels. Additionally, this system can be used to regulate illegal acts automatically such as illegal negligence of hazardous materials. And the system can be applied to the study about an application scheme as a guideline for transporting hazardous materials because there is no certain management system and act of toxic substances in Korea.

• The Korean Journal of Air & Space Law and Policy
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• v.8
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• pp.231-248
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• 1996

이 논문(論文)은 한국(韓國)의 우주(宇宙) 산업(産業) 발달(發達)과 그 과정(過程)을 고찰(考察)하고 현재 진행 중인 통신위성(通信衛星)의 개발(開發)과 그 사업(事業)을 뒷받침해 주는 국가(國家)의 정책(政策)을 살펴보고 있다. KOREASAT라고 명명(命名)된 통신위성(通信衛星) 개발(開發)에 현재 여러 기관이 관계(關係)하고 있으나 그 중 KARI(한국항공우주연구소(韓國航空宇宙硏究所)), ETRI(전자통신연구소(電子通信硏究所)), SERI(시스템공학연구소(硏究所)), KAIST(한국과학기술연구소(韓國科學技術硏究所)) 등이 중추적인 연구(硏究)를 하고 있다. 특히 이 논문(論文)에서는 아래와 같은 문제(問題)를 다루고 있다 첫째, 최근(最近) 한국우주개발(韓國宇宙開發) 상황(狀況) 둘째, 장기(長期) 우주개발(宇宙開發) 계획(計劃) 셋째, 현재(現在) 우주개발(宇宙開發) 상황(狀況)과 미래(未來) 우주개발(宇宙開發)에 관련한 정책(政策)적 문제(問題) 넷째, 한국(韓國) 우주개발(宇宙開發)과 정책(政策) 방향(方向)에 대한 의견(意見) 최근의 한국우주개발(韓國宇宙開發) 상황(狀況)은 크게 한국(韓國)의 통신위성(通信衛星) 사업(事業)인 Koreasat program과 다목적 위성사업(衛星事業)인 KOMSAT로 나타나는데 한국(韓國)의 최초 상업용(商業用) 위성(衛星)인 Koreasat는 1호가 1995년도에 발사(發射)되었으나 정상궤도(正常軌道) 진입(進入)에 문제(問題)가 발생하여 발사업체(發射業體)로부터 보상문제(補償問題)가 제기(提起)되기도 하였으나 2호는 성공리에 발사(發射)되었다. 미국항공우주회사(美國航空宇宙會社)와 공동(共同)으로 개발(開發)중인 새로운 과학위성(科學衛星)인 KOMSAT는 한국우주과학기술(韓國宇宙科學技術)을 한단계 더 발전(發展)시킬 수 있을 것이고 1999년도에 발사(發射) 계획(計劃)이다. 한국항공우주연구소(韓國航空宇宙硏究所) 중심(中心)의 장기(長期) 우주개발(宇宙開發) 계획(計劃)에서 제시(提示)하는 4가지 우주개발(宇宙開發)의 기본목표(基本目標)는 첫째, 우주산업응용산업(宇宙産業應用産業)의 상호협조개발(相互協助開發)에 의한 우주산업(宇宙産業) 육성(育成) 둘째, 한국(韓國)의 현재 우주산업상황(宇宙産業狀況)에 알맞은 특정분야(特定分野)를 선정(選定)하고 이 분야(分野)에서 최단기에 세계(世界) 최고의 기술수준을 성취(成就)하도록 집중(集中) 셋째, 외국과 긴밀한 협조(協助)로 선진기술(先進技術)의 습득(習得) 넷째, 체계적이고 통합(統合)된 장기우주산업발전(長期宇宙産業發展) 계획(計劃) 성립(成立) 등이다. 이러한 계획(計劃)에 주요 사안(事案)으로는 2015년까지 19기의 인공위성(人工衛星) 보유(保有)를 위한 제작계획(製作計劃)과 2010년까지 발사체(發射體) 개발(開發)을 마련하는 것이다 현재 우주활동(宇宙活動)에 관련된 문제(問題)는 주로 Koreasat의 서비스와 사용계획(使用計劃)에 대한 것으로 위성개발사업(衛星開發事業)에 있어서 관련 정부부서간(政府部署間)에 의견(意見)을 달리하고 있는 형태이다. 한국통신(韓國通信)과 정보통신부(情報通信部)는 위성(衛星)의 DBS 트랜스폰더에 대해 디지털 방식(方式)을 적용(適用)할 것을 제안(提案)했지만 공보처(共報處)는 반대(反對)의 입장(立場)을 표명(表明)한 것과 방송국(放送局)의 관리(管理)와 통제(統制)는 공보처(共報處)에 있고 무선통신표준(無線通信標準)에 대한 면허(免許)는 정보통신부(情報通信部)에 있기 때문에 방송국(放送局)에 대한 면허(免許)는 각기 다른 두 단계(段階)로 구성(構成)되는 문제(問題)가 발생(發生)한다. 또한 DBS 서비스에서 사기업(私企業)의 참여(參與)와 관련하여 재벌(財閥)의 참여(參與)를 허용(許容)하느냐의 여부(與否)의 논쟁(論爭)이다. 다음으로 미래(未來) 우주산업개발(宇宙産業開發)에 관한 정책문제(政策問題)를 살펴보면 국가적(國家的) 차원(次元)에서 조직적(組織的)인 육성책(育成策)에 대한 문제(問題)로 현재 주관 부처가 과학기술처(科學技術處)와 통상산업부(通商産業部)로 나뉘어 추진(推進)되고 있다는 점이다. 그리고 차세대(次世代) 통신위성개발(通信衛星開發) 계획(計劃)에 대한 문제(問題)로 최소 2${\sim}$4개의 궤도확보(軌道確保)와 이미 정상궤도(正常軌道) 진입(進入) 실패(失敗)에 따른 Koreasat 1호의 생명단축(生命短縮)으로 새로운 통신위성(通信衛星)을 4년이내에 발사(發射)해야 한다는 문제(問題)이다. 결론적으로 장기(長期) 우주개발계획정책(宇宙開發計劃政策)에 있어서 첫째, 국제적 우주개발사업(宇宙開發事業)에 대한 적극적(積極的) 참여(參與), 둘째, 우주(宇宙)에서 독립적(獨立的)인 활동(活動)을 할 수 있는 국가안보체제(國家安保體制)의 개발(開發), 셋째, 국가(國家) 위상(位相)의 발전(發展)과 우주개발(宇宙開發)을 위한 인력활용(人力活用)의 개발(開發), 넷째, 무한한 우주(宇宙)에 도전(挑戰)할 수 있는 우수(優秀)한 인재(人才)의 교육(敎育), 다섯째, 21세기를 대비(對備)하여 한국(韓國)의 우주개발정책(宇宙開發政策)의 결정(決定) 등이 고려(考慮)되어야 할 5가지 요소(要所)들이다. 그리고 막대(莫大)한 비용(費用)이 드는 우주개발사업(宇宙開發事業)을 효율적으로 추진(推進)하기 위해서는 국가(國家) 최고(最高) 지도자(指導者)의 직접지휘(直接指揮)를 받는 정부기구(政府機構)가 수립(樹立)되어 정부차원(政府次元)에서 추진(推進)하되 산학연(産學硏)이 협조(協助)하여 우주개발계획(宇宙開發計劃)을 추진(推進)하여야 할 것으로 본다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.141-146
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• 2018

Recently, location recognition technology has attracted much attention, especially for locating people or objects in an indoor environment without being influenced by the surrounding environment GPS technology is widely used as a method of recognizing the position of an object or a person. GPS is a very efficient, but it does not allow the positions of objects or people indoors to be determined. RFID is a technology that identifies the location information of a tagged object or person using radio frequency information. In this study, an RFID system is constructed and the position is measured using tags. At this time, an error occurs between the actual and measured positions. To overcome this problem, a neural network is trained using the measured and actual position data to reduce the error. In this case, since the number of read tags is not constant, they are not suitable as input values for training the neural network, so the neural network is trained by converting them into center-of-gravity inputs and median value inputs. This allows the position error to be reduce by the neural network. In addition, different numbers of trained data are used, viz. 50, 100, 200 and 300, and the correlation between the number of data input values and the error is checked. When the training is performed using the neural network, the errors of the center-of-gravity input and median value input are compared. It was found that the greater the number of trained data, the lower the error, and that the error is lower when the median value input is used than when the center-of-gravity input is used.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.61-74
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• 2005

Digital Multimedia Broadcasting(DMB) is a reliable multi-service system for reception by mobile and portable receivers. DMB system allows interference-free reception under the conditions of multipath propagation and transmission errors using COFDM modulation scheme, simultaneously, needs powerful channel error's correction ability. Viterbi Decoder for DMB receiver uses punctured convolutional code and needs lots of computations for real-time operation. So, it is desired to design a high speed and low-power hardware scheme for Viterbi decoder. This paper proposes a combined add-compare-select(ACS) and path metric normalization(PMN) unit for computation power. The proposed PMN architecture reduces the problem of the critical path by applying fixed value for selection algorithm due to the comparison tree which has a weak point from structure with the high-speed operation. The proposed ACS uses the decomposition and the pre-computation technique for reducing the complicated degree of the adder, the comparator and multiplexer. According to a simulation result, reduction of area $3.78\%$, power consumption $12.22\%$, maximum gate delay $23.80\%$ occurred from punctured viterbi decoder for DMB system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• Information Systems Review
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• v.9 no.2
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• pp.15-39
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• 2007

Mobile games have emerged as the most innovative entertainment technology, adding new revenue streams, taking advantage of the potential of wireless applications and service offerings. Mobile games, like any other types of computer game, offer a unique value for users in providing an exciting digital experience in virtual worlds. In this paper, we attempt to investigate the demographic factors which play critical roles in determining the level of playing times; classify mobile gamers based on their motives for playing games; and empirically test differences in their demographic factors and mobile game usage. Statistical results show that significant differences in playing times exist, depending upon their age, gender, mobile device, mobile phone usage, mobile game experiences, and preferred games genres. Applying Factor analysis, we have identified Escape, Social interaction, Challenge and Competition, Fantasy, Diversion and Relaxation, Ease of Accessibility as key motivators for playing mobile games. Additional cluster analysis shows that the categorization of gamers, according to their usage habits and the key motivators for playing, can be made as follows: Multi-gamers, Communication-focused gamers and Mobile active-gamers. Further correlation of these grouping with socio-economic data shows the significant differences in gaming habits and patterns of mobile phone use.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.51-62
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• 2002

EMI/EMS 측정을 위해서는 주변 전자파 잡음(background noise)이 낮은 야외시험장(Open Area Test Site)이 가장 바람직하나, 근래 전자(전기 기기 사용의 증가와 방송.무선통신 시스템의 다양화로 인한 인공잡음(artificial noise)의 증대로 조건에 부합된 부지 선정이 어렵고, 설치 비용이 매우 크며 날씨 변화에 따라 시험 계획이 변경 될 수도 있는 단점이 있다. 전자파 분-무반사실(Semi Anechoic Chamber)은 대부분의 환경 잡음을 감쇠시키므로 야외시험장처럼 장소의 구애를 받지 않아 도시나 혹은 제품 생산지 가까이에 설치 운용이 가능하다. 그러나 큰 설치 공간과 많은 시설 유지 비용을 필요로 하며, 저주파 대역에서는 반사에 의한 공진을 완전히 제거할 수 없어 성능이 떨어진다. 또한, 최근 컴퓨터 CPU의 동작주파수가 급속하게 높아지고 PCS, IMT-2000 등과 같은 이동전화의 사용주파수도 계속해서 높아짐에 다라 미연방통신위원회(Federal Communication Commission)에서는 5㎓까지의 복사 방출 시험을 요구하고 있다. IEC 61000-4-3 복사 내성 시험규격도 휴대폰 주파수인 2㎓까지 확장되었으며 IMT-2000, Bluetooth 등 새로운 이동통신서비스가 속속 개발됨에 따라 18㎓ 까지 시험 주파수가 확장되는 추세이다. 그러나, 현재 국내 각 연구실에서 보유하고 있는 야외시험장이나 전자파 반-무반사실의 경우 1㎓이상에서의 시험이 곤란하여 수 ㎓주파수대역에서 시험이 가능한 복사 및 내성시험 시설이 필요하게 되었다. 이러한 문제점들을 해결하기 위해 고안된 대용 측정 시설 중 대표적인 것이 TEM 셀이나 GTEM셀과 같은 TEM 도파관(waveguide) 형태의 장비들이다. 이들은 본래 EMS 측정을 위한 장비이지만 협소한 공간이나 외부와의 전자파 간섭의 우려가 없고, 설치가 비교적 자유로워 여러 연구기관에서 도파관 원리를 이용한 측정 방식을 연구(개발하여 범용적인 전자파 적합성 측정 장비로서 활용하고 있다. 야외시험장과 무반사실 등이 안테나에 의한 피시험기기 주변 공간에서의 1점 측정으로 인해 시험 시간이 많아 소요되는 공통적인 단점이 있는 반면, TEM 도파관에 의한 측정은 일단 피시험기기의 모델링 정보만 얻어지면 계산에 의해 EMI 측정을 바로 할 수 있다. <표 1>에서 현재 상용화되어 사용되고 있는 TEM/GTEM 셀, 야외 시험장 및 전자파 무반사실에 대해 EMI 측정과 관련된 몇 가지 사안에 대해 비교하였다. 본 문서에서는 야외시험장이나 전자파 반-무반사실 등과 같은 기존 EMI/EMS 측정 시설의 단점을 보완하고, 광대역 특성을 갖는 대용 측정 시설로서의 TEM 도파관에 대해 소개하고 야외시험장 결과와의 상관관계 알고리즘 및 표준화 동향에 대해 기술하였다. 2절에서는 대표적인 TEM 도파관 구조의 측정 시설인 TEM 셀과 GTEM 셀의 전기적.구조적 특징에 대해 간단히 기술하고, 3절에서는 TEM 셀과 GTEM 셀에서이 측정결과를 이용하여 야외 시험장 결과를 얻어내는 상관관계 알고리즘에 대해 기술하였다. 4절에서는 IEC/CISPR와 TC77에서의 표준화 활동을 중심으로 현재 진행중인 TEM 도파관 관련 표준화 동향과 내용에 대해 기술하고자 한다.