• 지능정보연구
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• 제15권1호
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• pp.123-140
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• 2009

협업필터링은 상품을 추천하고자 하는 고객과 유사한 구매 행태를 보이는 고객들의 구매 정보를 반영하여 추천대상 고객이 아직 구매하지 않은 상품에 대한 선호도를 예측한 후 선호도가 높을 것으로 예측되는 상품을 추천해주는 시스템이다. 그러나 신규고객의 경우에는 과거 구매 이력의 부재로 선호도를 예측할 수 없어 추천이 어렵게 되는 신규고객 추천문제가 발생하게 된다. 이러한 신규고객 추천문제를 해결하기 위해 기존에 제시되었던 방법들은 추천의 정확도가 낮거나, 추천에 필요한 정보 획득이 어렵거나, 추천 전에 고객이 능동적으로 질의에 응답해야 하는 부담이 있는 등의 문제로 인하여 그 실효성이 매우 낮다. 따라서 기존의 신규고객 추천 방법의 한계를 극복할 수 있는 새로운 접근방법의 필요성이 대두되고 있다. 본 연구에서는 사회네트워크 분석에서 관계 구조적 특성을 분석하기 위해 널리 활용 되고 있는 중심성 개념을 협업필터링에 적용하여 신규고객의 이웃고객을 찾고 그 이웃고객들의 구매정보를 이용하여 신규고객에게 상품을 추천하는 방법을 제시한다. 추천 프로세스는 구매 유사도 분석, 고객 네트워크 구성, 이웃고객 형성, 신규고객 상품추천 단계로 구성된다. 제시한 추천방법의 성능을 평가하기 위하여 국내 유명 백화점 중의 하나인 H백화점의 고객 구매 데이터를 사용하여 실험하였다. 실험 결과로부터 제시한 추천방법이 기존의 신규고객 추천방법들과 비교하여 추천의 정확도는 높으면서도, 구매정보 외에 인구통계정보 등과 같은 추가 정보가 필요하지 않으며, 추천 전에 고객이 능동적으로 질의에 응답할 필요가 없는 새로운 방법임을 알 수 있었다.

• International Journal of Aeronautical and Space Sciences
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• 제12권4호
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• pp.379-384
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• 2011

This paper performs numerical prediction of fuel temperature in the fuel tanks of unmanned air vehicles for both ground static non-operating and in flight transient conditions. The calculation is carried out using a modified Dufort-Frankel scheme. For this calculation, it is assumed that a non-operating vehicle on the ground is subjected to repeating daily cycles of ambient temperature with solar radiation and wind under 1%, with a 20% probability of hot day conditions. The energy conservation equation is used as the governing equation to calculate heat transfer between the fuel tank surface and the ambient environment. Results of the present analysis may be used as the estimated initial values of fuel temperatures in a vehicle's fuel tank for the purpose of analyzing transient fuel temperatures during various flight missions. This research also demonstrates that the fuel temperature of the front tank is higher than that of the rear tank, and that the difference between the two temperatures increases in the later phases of flight due to the consumption of fuel.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1286-1291
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• 2017

In this paper, we propose an indoor positioning system that makes use of the attenuation model for IEEE 802.11 Channel State Information (CSI) in order to determine its distance from an Access Point (AP) at a fixed position. With the use of CSI, we can mitigate the problems present in the use of Received Signal Strength Indicator (RSSI) data and increase the accuracy of the estimated mobile device's location. For the experiments we performed, we made use of the Intel 5300 Series Network Interface Card (NIC) in order to receive the channel frequency response. The Intel 5300 NIC differs from its counterparts in that it can obtain not only the RSSI but also the CSI between an access point and a mobile device. We can obtain the signal strengths and phases from subcarriers of a system which in turn means making use of this data in the estimation of a mobile device's position.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.134.2-134
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• 2001

This paper treats the implementation of a statically stable control system for a biped walking robot with 10 degrees-of-freedom. Statically stable walking of a biped robot can be realized by keeping the center of mass (COM) inside the sole of the supporting foot (or feet) during single-support or double-support phases. We predetermined five static positions for walking based on the COM method. The positions can be represented by the length of the gait, the width between the feet, the height of the foot and two parameters in the hip movement. With the five parameters, we calculated the position trajectory. And we got the angular trajectories of 10 joints from the posit ion trajectory using the position tracking control and neural network. By tracking the angular trajectories, the robot can walk maintaining stability. We implemented walking of a biped robot throught the above ...

• 한국군사과학기술학회지
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• 제13권4호
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• pp.650-658
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• 2010

Recently Korea Army developed the TICN which is the next army tactical communication system. The TICN will support ability from under environment, strategy maneuver communication system of integrated army dimension overcome and NCW. If the IER(Information Exchange Requirement) phases 3 of the future application system, the analysis that a transmission ability of the TICN is the uncapable is govern. The TICN tactical backbone's ability is very important. Therefore, network efficiency index in application and analysis of the standard protocol for the data transmission guarantee are obliged. For the TICN tactical backbone, this paper analyzes of routing protocol efficiency index and compares to superiority of the OSPF(v2) and integrated IS-IS protocols in the tactical environment. Conclusively we proposed that integrated IS-IS protocol is more suitable for TICN backbone routing protocol.

• 한국멀티미디어학회논문지
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• 제7권12호
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• pp.1692-1699
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• 2004

Many researchers have developed various techniques for detection of human faces in ordinary still images. Face detection is the first imperative step of human face recognition systems. The two main problems of human face detection are how to cutoff the running time and how to reduce the number of false positives. In this paper, we present frontal and near-frontal face detection algorithm in still gray images using a thick edge image and neural network. We have devised a new filter that gets the thick edge image. Our overall scheme for face detection consists of two main phases. In the first phase we describe how to create the thick edge image using the filter and search for face candidates using a whole face detector. It is very helpful in removing plenty of windows with non-faces. The second phase verifies for detecting human faces using component-based eye detectors and the whole face detector. The experimental results show that our algorithm can reduce the running time and the number of false positives.