• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.5C
• /
• pp.399-410
• /
• 2002

Web cache, which is functionally another word of proxy server, is located between client and server. Web cache has a limited storage area although it has broad bandwidth between client and proxy server, which are usually connected through LAN. Because of limited storage capacity, existing objects in web cache can be deleted for new objects by some rules called replacement algorithm. Hit rate and byte-hit rate are general metrics to evaluate replacement algorithms. Most of the replacement algorithms do satisfy only one metric, or sometimes none of them. In this paper, we propose two replacement algorithms to achieve both high hit rate and byte-hit rate with great satisfaction. In the first algorithm, the cache is appropriately partitioned according to file types as a basic model. In the second algorithm, the cache is composed of two levels; the upper level cache is managed by the basic algorithm, but the lower level is collectively used for all types of files as a shared area. To show the performance of the proposed algorithms, we evaluate hit rate and byte-hit rate of the proposed replacement algorithms using the trace driven simulation.

• The Journal of the Korea Contents Association
• /
• v.7 no.6
• /
• pp.1-8
• /
• 2007

In electronic commerce, it is important for users to recommend the proper item among large item sets with saving time and effort. Therefore, if the recommendation system can be recommended the suitable item, we will gain a good satisfaction to the user. In this paper, we proposed the associative relation clustering split method in the collaborative filtering in order to perform the accuracy and the scalability. We produce the lift between associative items using the ratings data. and then split the node group that consists of the item to improve an efficiency of the associative relation cluster. This method differs the association about the items of groups. If the association of groups is filled, the reminding items combine. To estimate the performance, the suggested method is compared with the K-means and EM in the MovieLens data set.

• Journal of the Korea Society for Simulation
• /
• v.23 no.1
• /
• pp.1-10
• /
• 2014

A cloud computing is one of a parallel and distributed computing. The cloud computing provides some service for user with virtual resources. However, a user's service request does not show a time pattern. As a result, each resource also shows a different availability at the same time. This difference affects a quality of service (QoS) and a resource selection for users. Therefore, we propose the resource availability-based multi auction model for cloud service reservation and resource brokering system. The proposed system is to select the proper resource provider based on the users' request. The proposal adopts the multi phase of the auction to transact resources. The system evaluates the available factor of each resource on the auction phase, and finally reserves the service on the adaptive queue. The proposed model shows the better performance than other existing method.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.3
• /
• pp.229-236
• /
• 2011

In this paper we present light weighted English-to-Korean and Korean-to-English mobile translators on smart phones. For natural translation and higher translation quality, translation engines are hybridized with Translation Memory (TM) and Rule-based translation engine. In order to maximize the usability of the system, we combined an Optical Character Recognition (OCR) engine and Text-to-Speech (TTS) engine as a Front-End and Back-end of the mobile translators. With the BLEU and NIST evaluation metrics, the experimental results show our E-K and K-E mobile translation equality reach 72.4% and 77.7% of Google translators, respectively. This shows the quality of our mobile translators almost reaches the that of server-based machine translation to show its commercial usefulness.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.2
• /
• pp.51-62
• /
• 2022

This study suggests a design of predictive modeling for a hospital fall risk based on inpatients' posture. Inpatient's profile, medical history, and body measurement data along with basic information about a bed they use, were used to predict a fall risk and suggest an algorithm to determine the level of risk. Fall risk prediction is largely divided into two parts: a real-time fall risk evaluation and a qualitative fall risk exposure assessment, which is mostly based on the inpatient's profile. The former is carried out by recognizing an inpatient's posture in bed and extracting rule-based information to measure fall risk while the latter is conducted by medical staff who examines an inpatient's health status related to hospital fall risk and assesses the level of risk exposure. The inpatient fall risk is determined using a sigmoid function with recognized inpatient posture information, body measurement data and qualitative risk assessment results combined. The procedure and prediction model suggested in this study is expected to significantly contribute to tailored services for inpatients and help ensure hospital fall prevention and inpatient safety.

• Journal of Korea Entertainment Industry Association
• /
• v.15 no.3
• /
• pp.279-287
• /
• 2021

The purpose of this study is to analyze the changes of the cognitive function and health-related quality of life. Study subjects were 35 elderly living alone and they participated in the cognitive program for 8 weeks regularly. The assessment of cognitive function was used by the Loewenstein occupational therapy cognitive assessment battery and the orientation, visual attention, spatial perception, motor praxis, visuomotor organization, thinking operation, and attention. The assessment of health-related quality of life was used by the Short form-8 health survey and the gerneral health condition, physical function and role, pain, vitality, social function, mental health, and emotional role. As the results, all the results of variables showed the statistically significant increase after the participation in the cognitive program. To improve the cognitive function and health quality of life of the elderly living alone, the participation in the cognitive program should be considered.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.12
• /
• pp.189-195
• /
• 2022

The Korean government has made it a major national task to contribute to the revitalization of the creative economy, such as creating new industries and jobs, by encouraging the private opening and utilization of public data. The Korean government is promoting public data quality improvement through activities such as conducting public data quality management level evaluation for high-quality public data retention. However, there is a difference in diagnosis results depending on the understanding and data expertise of users of the public data quality diagnosis tool. Therefore, it is difficult to ensure the accuracy of the diagnosis results. This paper proposes a public data quality management level evaluation domain rule mapping model applicable to validation diagnosis among the data quality diagnosis standards. This increases the stability and accuracy of public data quality diagnosis.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.446-446
• /
• 2023

우리나라는 물의 재이용 촉진 및 지원에 관한 법률에 따라 수자원의 지속 가능한 이용을 목적으로 빗물이용시설의 설치 및 운영을 법·제도적으로 의무화하고 있으며, 위 법에 근거하여 지방자치단체에서는 빗물이용시설의 설치를 장려하기 위한 재정 지원 정책을 시행하고 있다. 환경 투자사업의 일환인 빗물이용시설 설치 사업은 장기간에 대한 경제성 분석이 요구되며, 분석에 이용된 경제성 분석 방법 및 사회적 할인율에 따라 분석 결과가 상이할 수 있다. 이에 따라, 이 연구에서는 순현재가치와 편익-비용 비율을 비교·검토하여 빗물이용시설의 경제성 분석에 적합한 방법을 제시하였으며, 경제성 분석에서 불확실한 요소인 사회적 할인율과 물가상승률에 대한 민감도 분석을 통해 두 요소의 불확실성을 평가하였다. 분석 대상 시설은 인천 청라지구 1공구에 계획된 빗물이용시설이며, 경제성 분석 기간은 지방공기업법 시행규칙에 제시된 건축물의 내용 연수인 30년으로 하였다. 편익-비용 비율을 이용하여 빗물이용시설의 경제성을 분석한 결과, 저류용량이 285 m³에서 최대 수익률이 나타났으며, 순현재가치는 저류용량이 1105 m³일 때 최대 수익이 발생하는 것으로 분석되었다. 분석 대상 지역의 경우에 285 m³에 대한 양적 신뢰도는 7.3%로 빗물이용시설의 효과를 기대하기 어려운 결과이며, 이와 같은 결과는 편익-비용 비율이 사업의 경제성을 수익률로 평가함에 따라 투자 규모를 반영하지 않는 한계로 인한 것으로 판단된다. 사회적 할인율과물가상승률에 대한 민감도 분석 결과, 사회적 할인율이 낮아지고 물가상승률이 높아짐에 따라 빗물이용시설의 저류용량과 그에 상응하는 최대 순현재가치가 커지는 경향을 보였다. 이는 미래가치를 높게 평가할수록 빗물이용시설의 저류용량이 크게 설계될 수 있음을 의미한다.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.4
• /
• pp.611-616
• /
• 2023

ECG(electrocardiogram) is a test used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the cause of all heart diseases can be found. Because the ECG signal obtained using the ECG-KIT includes noise in the ECG signal, noise must be removed from the ECG signal to apply to the deep learning. In this paper, the noise of the ECG signal was removed using the digital IIR Butterworth low-pass filter. When the performance evaluation of the three activation functions, sigmoid(), ReLU(), and tanh() functions, was compared using the deep learning model of LSTM, it was confirmed that the activation function with the smallest error was the tanh() function. Also, When the performance evaluation and elapsed time were compared for LSTM and GRU models, it was confirmed that the GRU model was superior to the LSTM model.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.5
• /
• pp.462-469
• /
• 2023

In this study, we propose a method for evaluating the risk of collision between ships to support determination on the risk of collision in a situation in which ships encounter each other and to prevent collision accidents. Because several uncertainties are involved in the navigation of a ship, must be considered when evaluating the risk of collision. We apply the Dempster-Shafer theory to manage this uncertainty and evaluate the collision risk of each target vessel in real time. The distance at the closest point approach (DCPA), time to the closest point approach (TCPA), distance from another vessel, relative bearing, and velocity ratio are used as evaluation factors for ship collision risk. The basic probability assignments (BPAs) calculated by membership functions for each evaluation factor are fused through the combination rule of the Dempster-Shafer theory. As a result of the experiment using automatic identification system (AIS) data collected in situations where ships actually encounter each other, the suitability of evaluation was verified. By evaluating the risk of collision in real time in encounter situations between ships, collision accidents caused by human errora can be prevented. This is expected to be used for vessel traffic service systems and collision avoidance systems for autonomous ships.