• 한국정보통신학회논문지
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• 제18권6호
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• pp.1395-1400
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• 2014

근태관리 기록은 인사관리의 핵심적인 데이터로서 피고용인의 임금을 계산하기 위한 기초 데이터이다. 그러나 기존의 기계식 또는 전자식 근태관리 시스템은 부정확하고 초기 도입 비용이 매우 크다는 단점이 있다. 이 논문에서는 피고용인의 스마트기기를 이용한 근태관리 시스템을 설계하고 구현한다. 피고용인의 근태 자료를 기록하기 위하여 스마트기기의 맥 주소와 와이파이 무선접근점의 맥 주소를 이용하여 피고용인의 위치 정보를 획득하고 획득된 위치정보를 이용하여 피고용인의 출/퇴근 자료를 서버에 전송한다. 기존의 소유하고 있는 스마트기기와 와이파이 무선접근점을 사용하기 때문에 초기도입 비용이 낮아서 소규모업자들도 쉽게 자동화된 근태관리 시스템을 사용할 수 있는 장점이 있다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.83-88
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• 2006

Many applications in the area of location-based services and personal navigation require nowadays the location determination of a user not only in outdoor environment but also indoor. To locate a person or object in a building, systems that use either infrared, ultrasonic or radio signals, and visible light for optical tracking have been developed. The use of WiFi for location determination has the advantage that no transmitters or receivers have to be installed in the building like in the case of infrared and ultrasonic based location systems. WiFi positioning technology adopts IEEE802.11x standard, by observing the radio signals from access points installed inside a building. These access points can be found nowadays in our daily environment, e.g. in many office buildings, public spaces and in urban areas. The principle of operation of location determination using WiFi signals is based on the measurement of the signal strengths to the surrounding available access points at a mobile terminal (e.g. PDA, notebook PC). An estimate of the location of the terminal is then obtained on the basis of these measurements and a signal propagation model inside the building. The signal propagation model can be obtained using simulations or with prior calibration measurements at known locations in an offline phase. The most common location determination approach is based on signal propagation patterns, namely WiFi fingerprinting. In this paper the underlying technology is briefly reviewed followed by an investigation of two WiFi positioning systems. Testing of the system is performed in two localization test beds, one at the Vienna University of Technology and the second at the Hong Kong Polytechnic University. First test showed that the trajectory of a moving user could be obtained with a standard deviation of about ${\pm}$ 3 m.

• 한국컴퓨터정보학회논문지
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• 제10권6호
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• pp.269-278
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• 2005

인터넷 차단 시스템은 기업내부에서 직원들의 인터넷 사용 내역에 대한 세부적 통제 수단으로 많이 각광받고 있다. 인터넷 차단 시스템은 기업의 인터넷 사용 형태에 많은 변화를 가져오지만 아직까지 이의 효과에 대한 세부적인 연구가 진행된 사례가 없다. 본 논문은 인터넷 차단 시스템의 도입에 대한 경제적 효과를 분석하여 인터넷 차단 시스템을 현재 운영중이거나 도입에 대하여 검토 중인 기업의 투자 및 운영에 대한 의사결정지표를 제시한다. 기존 연구를 통해 인터넷 차단 시스템에 대한 비용 및 효과 측정 수단을 개발하였으며, 실제 기업 전산망에 인터넷 차단 시스템 및 관련 측정 시스템을 구축하여 시스템 구축 전후의 추이 변화를 측정하여 효과 분석에 사용했다. 결론적으로 인터넷 차단 시스템이 일부 역효과에도 불구하고 기업의 생산성 향상 및 통신 대역폭의 개선에 매우 긍정적인 효과를 준다고 파악하였다.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.172-178
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• 2023

When the mobile device moves from the coverage of one access point to the radio coverage of another access point it needs to maintain its connection with the current access point before it successfully discovers the new access point, this process is known as handoff. During handoff the acceptable delay a voice over IP application can bear is of 50ms whereas the delay on medium access control layer is high enough that goes up to 350-500ms. This research provides a suitable methodology on medium access control layer of the IEEE 802.11 network. The medium access control layer comprises of three phases, namely discovery, reauthentication and re-association. The discovery phase on medium access control layer takes up to 90% of the total handoff latency. The objective is to effectively reduce the delay for discovery phase to ensure a seamless handoff. The research proposes a scheme that reduces the handoff latency effectively by scanning channels prior to the actual handoff process starts and scans only the neighboring access points. Further, the proposed scheme enables the mobile device to scan first the channel on which it is currently operating so that the mobile device has to perform minimum number of channel switches. The results show that the mobile device finds out the new potential access point prior to the handoff execution hence the delay during discovery of a new access point is minimized effectively.

• 한국문헌정보학회지
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• 제33권4호
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• pp.65-83
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• 1999

본 연구는 서지적으로 관련된 저작을 연결하고, 특정 저자의 상이한 이름이나 특정 저작의 상이한 서명을 직접 접근점으로 사용하기 위해, 전거표목을 배제한 시스템을 제안하고 있다. 이를 위해, 특정 접근점과 그 이형(異形)에 대한 참조와 이들간의 서지적 관계유형을 제공할 수 있는 레코드의 형식을 개발하여 참조시스템을 제안하였다. 아울러 전통적인 표목 및 상호참조의 기능을 본 시스템과 관련하여 검토하였다.

• Restorative Dentistry and Endodontics
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• 제27권4호
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• pp.432-440
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• 2002

The purpose of this study is to identificate root canal system including ideal access placement, root curvature, canal configuration, incidence of isthmus in mandibular incisors for success of endodontic treatment. 200 mandibular incisors were selected. The ideal access placement was determimed as follows. The teeth there radiographed from mesiodistal and buccolingual views using intraoral dental film. The image was divided into coronal, middle and apical third using the proximal film. Straight line access was determined by measuring the faciolingual canal width and placing points at midway point between the buccal and lingual wall at the junction of the middle and apical third and at the juntion of coronal and middle third of the root canal. A line was drawn connecting these two points extending through the crown of the tooth. The point at which the line crossed the external crown surface was recorded as facial, incisal, lingual. Degree of root curvature was determined by Schneider Protractor Method. Both section method and clearing method were used in this study. By section method, 100 mandibular incisors were embedded in clear resin and transeverse serial sectioned at 0.5, 1.0, 2.0, 3.0, 4.0, 5.0mm level from root apex. The resected surfaces were stained by methylene blue and examined under $\times$40 magnification with a stereomicroscope. By clearing method, 100 mandibular incisors were cleared in methysalicylate after decalcification with 10% nitric acid and evaluated under $\times$18 magnification with a stereomicroscope. The results were as follows ; 1. 29% had the center of the plotted straight-line access facial to incisal edge, whereas 71% had straight-line access at the incisal edge. When incisal wear classified as extensive, the straight-line access was plotted on the incisal edge 95.5%. When incisal wear classified as slight/none, the straight-line access was plotted on the facial 65.9%. 2. Degree of curvature of main canal was straight or almost straight, and only 10% in buccolingual direction had a degree of curvature greater than 20 degrees and 5.5% in mesiodistal direction had. 3. In section method, canal configuration analysis showed that 51% of the specimen classified as type I, 27% as type II, 12% as type III, 10% as type IV. For theses setions with two canals, the incidence of an isthmus was 36.7%, 64.3%, 79.2%, 96.3%, 97.4%, 97.6% at each level and highest in 3~5mm sections. 4. In clearing method, canal configuration analysis showed that 74% of the specimen classified as type I, 11% as type II, 6% as type III, 9% as type IV. These results suggested that traditional access from lingual should be moved as far toward the incisal as possible to locate and debride the lingual canal and root canal system should be cleaned, shaped completely and obturated three dimensionally for successful endodontic treatment.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3440-3446
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• 2015

오늘날, 사용자들은 스마트 폰, 태블릿 등의 장치를 사용하여 항상 인터넷 서비스를 즐길 수 있다. 이러한 일을 일어날 수 있도록 하는 기술 중 하나가 Wifi이다. 그러나 휴대용 무선기기 사용자 들은 속도가 느려지거나 연결이 안정적이지 않다고 자주 생각하게 된다. 반면에, 유대용 무선기기 사용자들은 사용 가능한 여러 개의 다른 무선 Wifi Access Point (액세스 포인트) 가 종종 존재 하는 것을 본다. 본 논문에서는 여러 Wifi 액세스 포인트 중 가장 좋은 Wifi 액세스 포인트로 연결을 주기적으로 변경하는 WiSMax라는 애플리케이션을 제안한다. WiSMax는 AP스캐닝을 통하여 기기 주변 AP의 메타정보를 비교하며 AP의 세기 값을 계산하여 실시간 세기의 변화를 보여주며 T주기마다 가장 적합한 AP를 n개 추천한다. 추천된 AP들 중 가장 좋은 신호의 AP를 추천하여 연결하는 방식으로 진행된다. 실험 결과 WiSMax는 기존 AP연결 알고리즘에 비해 평균 대략 15% 가량 다운로드가 빠르며, 신호의 세기 역시 평균 5dBm 높아 사용자에게 고속 인터넷 연결을 제공하는 것을 보여준다.

• 한국정보처리학회논문지
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• 제4권9호
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• pp.2354-2365
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• 1997

본 논문은 현대의 정보 통신 응용에서 접근제어 요구 사항의 복잡한 문제를 해결하기 위한 접근제어 매커니즘의 설계 방안을 제시한다. 본 논문에서는 자원의 기밀성, 무결성 및 가용성의 공통적 목적을 달성하기 위한 통합 정보 모델을 제안 하고, 신분-기반, 규칙-기반 및 직무-기반의 관점에서 각 관련된 정책과 규칙을 정의하였으며, 필요한 접근제어 오퍼레이션들을 구현하였다. 제안된 통합 정보 모델은 보안 레이블, 무결성 등급, 직무 및 소유권 등의 다단계 보안 정책을 기반으로 하여 자원에 대한 불법적인 접근을 방어할 수 있다.

• 한국도서관정보학회지
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• 제27권
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• pp.61-95
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• 1997

The purpose of this paper is to overview a recent dispute of the library of the 21st century in Korea and to suggest a desirable model of the future library. There are two visions of the future of library. The first is an access based library model(digital library) emphasizing the digital resources that are networked and browsable electronically. The second is an ownership-based library model(paper library) which emphasize the use of traditional print collections stored locally and physically browsable. A points of dispute between the paper library as storehouse and the digital library as gateway are an electronic informations versus printed materials, access versus ownership, information professional versus librarians. The idea that library as physical place and as cyberspace are diametrically o n.0, pposed is a fallacy and surrealistic opinion. Future library has to acquire, organize, preserve, and make accessible the collections that users want and need. In other words, future libraries need both ownership and access. Access to remote electronic resources must serve as a reasonable substitute for holdings of older material. Therefore, it is a balanced solution that the more heavily used or important materials be considered for ownership and selective information resources for access. No doubt, the traditional library and the digital library will be coexist in the 21 century.

• 대한원격탐사학회지
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• 제10권2호
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• pp.109-120
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• 1994

The study is aimed at the extraction of the groundwater potential areas utilizing the remotely sensed data from satellites. The results of the study are summarized as follows. Analyses of the existing operational wells for groundwater supply indicate that 81% of them are related with lineaments and 51% of them are located at the intersections of lineameters. Thus the features of lineaments are considered to be one of the most important parameters to extract a high potertial area of groundwater. Taking into acount features of lineament, high potential points were extracted from Landsat TM data based on the theory developed in this research, then verifications were made through actual drilling. The result of verification indicates that 9 points produces more 200 cubic meter/day which is the amount required from economical point of view for an operational use. Since the actual boring was not made on the recommended points for 4 points due to the difficulty of access to the exact points and of the approval for boring, they did not yield enough output. The result might have been improved if the exact points were bored and if the boring bad been made deeper, since the maximum depth of boring was limited to 62 meters.