핑거프린트를 이용하는 클라이언트 기반 실내 측위 시스템의 설계 및 구현

황원영,최창열 江原大學校 産業技術硏究所 2008 産業技術硏究 Vol.28 No.A

Recently, interests on positioning system for location-based services have been significantly increased. Many indoor environment systems using fingerprint scheme have been designed to take more accuracy of positioning, but they are inefficient in adapting to change of environments. In this paper, we focus on a client-based positioning system over WLAN for decreasing installation cost and adapting to change of environments. In the proposed system, APs with stable RSSI are selected as base APs independently for each reference point. Experimental results show that proposed system expands service area approximately 20% much than traditional systems using K-NN algorithm and needs only 20% modification process to fingerprint data compare with traditional systems whenever environment conditions are changed.

ESR을 이용한 동함유 모더나이트의 특성연구

최고열,이창용 서울産業大學校 1993 논문집 Vol.38 No.1

염산처리에 의하여 실리카 /알루미나 비가 다른 모더나이트를 제조하고, 여기에 동을 담지시켰다. 제조된 시료에 대하여 환원·산화처리 온도 및 동함량에 따른 동이온의 특성을 관찰하기 위하여 ESR 분석을 행하였다. 500℃에서 환원·산화처리한 시료에서 동이온은 이온교환시료의 동이온과 비슷한 특성을 나타내었다. 그러나 750℃에서 환원·산화처리한 시료의 경우 500℃에서 환원·산화처리한 시료와는 달리 환원·산화처리시 모더나이트 결정구조의 부분적인 변화에 기인하여 불포화배위의 유리 동이온이 존재하였다. Copper containing modernities which have different silica/alumina ratio were prepared by acid leaching, followed by impregnation with copper. ESR study on these mordenites was carried out to investigate the effect of redox treatment and copper content on the behavior of cupric ions in these samples. When the copper impregnated mordenites were redox-treated by hydrogen and oxygen at 500℃, the behavior of cupric ions in these samples was similar to that of cupric ions in the ion-exchanged mordenites. However, redox-treated at 750℃, coordinatively unsaturated cupric ions exist due to the slight change of mordenite structure during the high temperature redox treatment.

분리 트랜잭션 버스 기반 다중프로세서 시스템의 인터럽트 제어 및 동기화

최장열 강원대학교 정보통신연구소 1997 정보통신논문지 Vol.1 No.-

This paper presents the control module of the interrupt of the interrupt bus which supports asynchronous data transfers, interprocessor communications, and reliable interrupt synchronization for a split transaction bus based multiprocessors system. The multiprocessor interrupt control module is composed of interrupt requester, interrupt handler, and bus interface including bus arbitration, and supports direct interrupt, arbitration interrupt, and four interrupt vectors. The tight timing restriction on the interrupt receiving logic is relaxed by the state machine using both the interrupt data and the interrupt synchronization signal which are latched on the interrupt bus buffer. The interrupt bus malfunction due to the signal noise or the fault of a function module is avoided by keeping the operation procedure of each interrupt requester identical.

集合·關係·函數의 言語

최창렬 全北大學校 語學硏究所 1980 어학 Vol.7 No.-

언어연구의 가설적인 모델링의 방법을 논리적인 記號와 式으로 이루어지는 형식언어로 설정할 수 있다. 형식언어에서는 일반적으로 자연언어의 단어 대신 여러 가지 기호로 대치시켜 그 어휘로 삼기 때문에 ‘기호 언어’라 불리우고 기호언어의 文들은 소위 ‘式’이 되는 것이다. 言彙單位나 기호는 더 쪼개지지 않는 ‘단순표현’이고, 文이나 式은 단순표현이 일정한 규칙에 따라 서로 이어져 만들어진 복합표현이다. 일상언어에서나 기호언어에서나 단순표현의 수에는 한이 있으나 복합 표현의 수에는 한이 없다. 또한, 일상 언어의 단순 표현들은 대개의 경우 체언과 조사 또는 어간과 어미로 쪼갤 수 있지만, 기호언어에서의 단순 표현들은 더 쪼갤 수 없는 단위가 된다. 이제 이 기호언어의 모델링을 위하여 다음과 같이 몇 가지 기본 개념을 확실히 해 두기로 한다.

XOR 연산을 이용한 저비용 RFID 시스템의 보안 접근 제어 기법

최승술,최창열 강원대학교 정보통신연구소 2006 정보통신논문지 Vol.10 No.-

The security of RFID(Radio Frequency IDentification) systems has been an important and challenging issue. There have been a variety of research activities in the RFID security field. Usually, hash-based schemes have been introduced for access control between readers and tags. One of major drawbacks is the usage of many gates, so that the practical implementation becomes difficult in low-cost RFID system. In this paper, we propose a new access control technique which supports low-cost RFID systems with a few gates (e. g., 5000 gates). The proposed scheme based on XOR operation can efficiently implement low-cost RFID tags. Furthermore, the scheme guarantees the security from, eavesdropping, location tracking, replay attack, and spoofing by using a random secret key in every session.

치과용 니켈-티타늄 합금의 갈바닉 부식

최창혁,최기열,이중배 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

The purpose of this study was to evaluate the galvanic corrosion behavior of NT by coupling with other dental alloys in artificial saliva. The variation of galvanic current and common potential (mixed potential) were monitored as a function of time, and interpreted in terms of the electrochemical properties of each alloy. The effects of adding some constituents such as acid or chloride to the ordinary composition of artificial saliva were also estimated. For most cases of coupling, the significant current was observed only at early stage for several seconds or several minutes, then gradually diminished. The current value was affected by the excessive amount of acid or chloride added to artificial saliva, depending on their aggressiveness on each alloy ; the current was increased in the couples with HG, LG, VT, and decreased in the couples with AM and G2. The results were more complicated in the couples with AP and TC, where some mixed reaction occurred. The common potential was always between two corrosion potentials of alloys involved in the couple, and did not exceed the breakdown potential of alloy acted as anode except the case of coupling with AM in acid-containing artificial saliva. The coupling with AM was found to be the most susceptible to galvanic corrosion.

P2P 프록시 캐싱을 이용한 VOD 시스템의 성능 향상

최치규,이근정,최창열,최황규 강원대학교 정보통신연구소 2005 정보통신논문지 Vol.9 No.-

This paper proposes a new proxy caching scheme of VOD systems in P2P network environments. In our P2Proxy caching scheme, a proxy server is composed of a client group in which each client stores a part of stream receiving from a VOD server into its client buffer. Each streaming part of the clients is equal to a buffer size which is desired at request its hour. A single client receives the request stream from other clients as long as the parts of the stream are available in the client group. Otherwise, the missing parts of the stream which are not in the client group are directly received from the VOD server through another patching channel. In the experiments, we evaluate the performance of our proposed scheme and the result is compared with the existing P2P streaming systems.

SCSI 디스크 시스템의 모델링 및 중첩 선탐색

최창열,황기태 강원대학교 정보통신연구소 1998 정보통신논문지 Vol.2 No.-

The SCSI is the most popular disk I/O interface. In this paper, we propose a technique to improve disk I/O performance at the SCSI disk drive level. The proposed overlapped seek-ahead(OSA) algorithm based on the operational characteristics of intelligent disk drives exploits the idle time of the SCSI disk components such as disk head and DMA controller. The performance of the proposed algorithm is studied by using a SCSI I/O system simulator, which simulates the SCSI bus, command queue, processor, disk cache, etc. Results show that the OSA model reduces the response time for random disk accesses considerably. And the model is independent of operating systems and disk scheduling algorithms.

동화 관련 활동이 유아의 창의성 증진에 미치는 효과

권창길 ; 이기영 ; 고윤희 ; 최성열 김천대학교 2005 김천대학교 논문집 Vol.26 No.-

This study is to find out about the effect of children's stories and related activities on the creativity of children by conducting a research on 90 5-year-olds attending Kindergraten B in Gumi City and Kindergarten F ing Gimcheon City.

정보화사회에서의 상업교육

김창호,최종열,김진욱 부산대학교 사범대학 1996 교사교육연구 Vol.32 No.-

Today's business education is characterized both vocational business education and general education. Specialization as vocational business education and generalization with articulation from kindergarten to post secondary education are essential for manpower training on demand of information society. So, to educate information technology which is a basic element of information society is essential to guarantee both specialization and generalization. Information technology is being emerge as various forms - 'on-line' education 'on-line' university edu-port virtual classroom - in most areas of education. So, to teach information technology in secondary school is very important from this point of view of future human resource development. To make subjects of information technology (IT) and to educate IT are mainly charged by 'business education department' is a today's trend. Therefore schools that have provided education for and about business must be changed to meet the needs of information society.