• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.678-682
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• 2021

Reverberation Time (RT) with noise levels can affect speech recognition ability in a listening environment. The degree of influence may depend on reverberation times and modes of binaural hearing. In this study, Korean monosyllabic Word Recognition Scores (WRS) were investigated in 10 young normal hearing subjects under binaural conditions. The RT of 3.4 s and signal to noise ratio of 0 dB were used at 55 dB HL for diotic (noise with the same phase) and dichotic (noise with the fixed phase difference, π) conditions. The improvement in WRS was noted in dichotic hearing (p < 0.05) while the similar trend was not observed in diotic hearing. This data may be useful in analyzing psychoacoustic effects of RTs under noisy conditions.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.75-82
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• 2023

In collaborative filtering systems, the item rating prediction values calculated by the systems are very important for customer satisfaction with the recommendation list. In the time-aware system, predictions are calculated by reflecting the rating time of users, and in general, exponentially lower weights are assigned to past rating values. In this study, to find out whether the influence of rating time on the rating value varies according to various factors, the correlation between user rating value and rating time is investigated by the degree of user rating activity, the popularity of items, and item genres. As a result, using two types of public datasets, especially in the sparse dataset, significantly different correlation index values were obtained for each factor. Therefore, it is confirmed that the influence weight of the rating time on the rating prediction value should be set differently in consideration of the above-mentioned various factors as well as the density of the dataset.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.1-5
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• 2015

Recently, RF energy harvesting technology is a promising technology for small-size IoT(Internet of Things) devices such as sensor to resolve battery scarcity problem. When applied to existing cognitive radio networks, this technology can be expected to increase network throughput through the increase of cognitive user's operating time. This paper proposes a optimal channel-selection policy for RF energy harvesting CR networks model where cognitive users in harvesting zone harvest ambient RF energy from transmission by nearby active primary users and the others in non-harvesting zone choose the channel and communicate with their receiver. We consider that primary users and secondary users are distributed as Poisson point processes and contact with their intended receivers at fixed distances. Finally we can derive the optimal frame duration, transmission power and density of secondary user from the proposed model that can maximize the secondary users's throughput under the given several conditions and suggest future directions of research.

• Journal of agriculture & life science
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• v.43 no.5
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• pp.27-32
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• 2009

This study purposed to examine the effect of the horticultural therapy on activities of daily living and cognitive function of demented old adults in facilities. According to the results of evaluating BADL, the ability to perform daily activities decreased from 9.71 to 9.21 in the control group, but in the experimental group, the ability to perform daily activities increased significantly(p=.009) from 10.86 before the horticultural therapy to 12.43 after the therapy. According to the results of evaluating K- MMSE, the score decreased from 10.57 to 9.07 in the control group, but the experimental group showed a significant improvement in cognitive functions from 10.43 before the horticultural therapy to 13.29 after the therapy(p=.003). As presented above, the horticultural therapy was effective in improving activities of daily living and cognitive function of demented old adults.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.157-165
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• 2009

In this paper, we propose a distributed model that recognize ADLs of human can be occurred in daily living places. We collect and analyze user's environmental, location or activity information by simple sensor attached home devices or utensils. Based on these information, we provide a lifecare services by inferring the user's life pattern and health condition. But in order to provide a lifecare services well-refined activity recognition data are required and without enough inferred information it is very hard to build an ADL activity recognition model for high-level situation awareness. The sequence that generated by sensors are very helpful to infer the activities so we utilize the sequence to analyze an activity pattern and propose a distributed linear time inference algorithm. This algorithm is appropriate to recognize activities in small area like home, office or hospital. For performance evaluation, we test with an open data from MIT Media Lab and the recognition result shows over 75% accuracy.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.103-109
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• 2006

본 논문은 인지 및 행동 장애 재활 시스템을 구현하기 위하여 동영상인식 기반의CAMSHIFT 알고리즘을 적용시켰다. 주의력과 반응 시간을 측정하는 인지 장애 재활 시스템이 개발되었고 환자의 주의 집중력과 손 움직임의 조절력을 측정하고 시 지각 운동 능력을 측정하는 행동 장애 재활 시스템이 개발되었다. 실험은 중앙대학교 의료원 재활 의학과에서 실시하여 측정되었다. 본 논문에서 개발한 시스템은 훈련 과정을 객관적인 측정량과 오랫동안 연습할 수 있는 동기를 제공해 줌으로써 전통적인 치료법에 비해 흥미롭고 유용한 도구가 될 수 있음을 환자를 치료하는 치료사를 대상으로 PSS CogRehab 시스템과 비교하는 설문 조사를 통하여 증명한다.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.340-347
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• 2007

"유비쿼터스 컴퓨팅"과 "상황인지 컴퓨팅"이 점차 확산되어짐에 따라 유비쿼터스 환경이 급격하게 발전하면서 변화하고 있다. 이러한 변화로 인해 사용자 정보와 사용자 주변의 환경 정보를 파악하여, 적절한 시간에 적절한 서비스를 제공할 수 있는 기술과 인간과 컴퓨터 관계가 증가하면 할 수 록 인간과 인간의 관계처럼 좀 더 자연스러운 관계를 유지 할 수 있는 상황인지 컴퓨팅이라는 개념이 나타나기 시작하였다. 이러한 상황인지 컴퓨팅을 통하여 상황을 인지하고 사용자에게 필요한 정보를 제공하기 위해서는 상황을 정의 할 수 있는 상황인지 모델이 필요하다. 그러나 현재, 상황을 인지하기 위한 상황인지 모델에 관한 연구는 미비한 상태이다. 본 논문에서는 5W1H를 이용하여 상황을 정의하고, RFMatrix를 이용하여 주변 환경과 사람들과의 관계를 반영한 RFMatrix 기반의 상황인지 모델을 제안한다. 또한 제안된 RFMatrix모델의 유용성을 검증하기 위해 학습공간의 실험을 통하여 정확성을 검증하고자 한다.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.231-233
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• 2008

본 논문에서는 연계점전압의 변화율과 가속이득을 이용한 향상된 수동적 인지법을 제안하였다. 기존의 수동적 인지법과 비교하여 불검출영역의 감소를 확인하였고 적정한 가속이득 값을 설정하기 위하여 단독운전 검출 소요시간과 시스템 민감도를 분석하였으며 컴퓨터 시뮬레이션을 통해 제안한 알고리즘의 타당성을 검증하였다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.353-357
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• 2005

난황으로부터 인지질을 회수하기 위하여 전처리, 표면반응분석기법을 실시한 결과 인지질 95%이상 PC함량 55%의 제품을 생산할 수 있는 공정을 확립하였다. 난황 인지질 분리조건(액난황 100g 기준)은 알코올 농도 91.38%, 알코올 첨가량 1: 7.3, 균질온도 $29.22^{\circ}C$, 균질시간 5분으로 한 후 원심분리한 다음 여과후 진공농축하고 아세톤 100ml로 1회 세척하고 나서 여과지로 여과하고 $100^{\circ}C$, 40분 건조하거나 $40^{\circ}C$ 진공건조기에서 overnight 정도 건조과정을 휘발시키는 것이 바람직한 것으로 생각된다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.58
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• pp.19-27
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• 2006

Technologies to utilize the limited frequency resource more efficiently in spatial and temporal are accelerated. In this paper cognitive algorithms as brain of cognitive radio, kind and characteristics of databases which are necessary parts for algorithm were reviewed and summarized. And an example of cognitive engine on which database and algorithm are executed was described also. Because the current status of development of technologies relating to cognitive radio is at the initial stage, the best database, algorithm and engine for a cognitive radio were not suggested, but the direction of development and factors to be considered during development of relating technologies were explained.