• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.6
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• pp.635-642
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• 2003

Reinforcement learning got successful results in a lot of applications such as control and scheduling. Various function approximation methods have been studied in order to improve the learning speed and to solve the shortage of storage in the standard reinforcement learning algorithm of Q-Learning. Most function approximation methods remove some special quality of reinforcement learning and need prior knowledge and preprocessing. Fuzzy Q-Learning needs preprocessing to define fuzzy variables and Local Weighted Regression uses training examples. In this paper, we propose a function approximation method, Fuzzy Q-Map that is based on on-line fuzzy clustering. Fuzzy Q-Map classifies a query state and predicts a suitable action according to the membership degree. We applied the Fuzzy Q-Map, CMAC and LWR to the mountain car problem. Fuzzy Q-Map reached the optimal prediction rate faster than CMAC and the lower prediction rate was seen than LWR that uses training example.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.41-47
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• 2008

Cluster based fuzzy model tree has certain drawbacks to decrease performance of testinB data when over-fitting of training data exists. To reduce the sensitivity of performance due to over-fitting problem, we proposed a modified cluster based fuzzy model tree with node information. To construct model tree, cluster centers are calculated by fuzzy clustering method using all input and output attributes in advance. And then, linear models are constructed at internal nodes with fuzzy membership values between centers and input attributes. In the prediction step, membership values are calculated by using fuzzy distance between input attributes and all centers that passing the nodes from root to leaf nodes. Finally, data prediction is performed by the weighted average method with the linear models and fuzzy membership values. To show the effectiveness of the proposed method, we have applied our method to various dataset. Under various experiments, our proposed method shows better performance than conventional cluster based fuzzy model tree.

• Journal of Service Research and Studies
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• v.4 no.1
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• pp.83-93
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• 2014

Telemedicine is performed at a place far away from medical practice with physicians and patients by the means of communication appropriately. It will be identified in general the remote medical service to deliver the medical information and also defined as any action by interactive information communication technology. Medical services can be said to be fused as television, communication, computer, engineering of various technologies of information and communication applications. If doctors can not be reached due to distances away from the patient, Information technologies could be used to get medical information and to give expert advice provided by the system remotely. And it could be used patient care as well as medical administration, medical education, professional advice and consulting. In this paper, we take a look at the legal requirements of telemedicine for improving regulatory in the current law to investigate the matter.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.75-85
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• 2003

Laboratory model blast and in-situ rock blast tests were conducted to determine blast-induced stress wave propagation characteristics under different explosive types, different loading conditions and different mediums. Dynamic numerical approaches were conducted under the same conditions as experimental tests. Stress magnitudes at mid-point between two blast holes which were detonated simultaneously increased up to two times those of single hole detonation. The rise time of maximum stress in a decoupled charge condition was delayed two times that of a fully charged condition. Dynamic numerical analysis showed almost similar results to blast test results, which verifies the effectiveness of numerical approaches fur optimizing the tunnel blast design. Dynamic numerical analysis was executed to evaluate rock behavior and damage of the contour hole, the sloping hole adjacent to the contour hole in the road tunnel blasting pattern. The rock damage zone of the sloping hole from the numerical analysis was larger than that of the contour hole. Damage in the sloping hole can be reduced by using lower density explosive, by applying decoupled charge, or by increasing distance between the sloping hole and the contour hole.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.53-58
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• 2000

It was carried out consequence analysis(CA) of CNG (compressed natural gas) service station and we compared the results of CA of CNG service station with LPG service station which was installed by high Pressure gas law. The results of CA were that distance of CNG LFL was 1.5 times than the length of LPG LFL. Thermal radiation effect about CNG may not be showed damage of process facilities, but in the case of LPG, it was enough to have an large damage effect on a downtown. The thermal radiation of 37.5 $kw/m^2$ extended 12.6 m. Also, in the case of 12.5 $kw/m^2$ which was able to burn wood, the radiation effect of LPG is 3 times than CNG.

• Journal of Information Technology and Architecture
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• v.9 no.1
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• pp.57-66
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• 2012

Recently, with a rapidly growing of the mobile content market, a variety of mobile-based applications are being launched. But mobile devices, compared to the average computer, take a lot of effort and time to get the final contents you want to use due to the restrictions such as screen size and input methods. To solve this inconvenience, a recommender system is required, which provides customized information that users prefer by filtering and forecasting the information.In this study, an tailored multi-information recommendation system utilizing a Personalized information recommendation system on smartphone is proposed. Filtering of information is to predict and recommend the information the individual would prefer to by using the user-based collaborative filtering. At this time, the degree of similarity used for the user-based collaborative filtering process is Euclidean distance method using the Pearson's correlation coefficient as weight value.As a real applying case to evaluate the performance of the recommender system, the scenarios showing the usefulness of recommendation service for the actual restaurant is shown. Through the comparison experiment the augmented reality based multi-recommendation services to the existing single recommendation service, the usefulness of the recommendation services in this study is verified.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.1
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• pp.149-177
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• 1994

This study is practically focussed on the derivation of the formula of the reach of the catchment of urban community parks and the reached distance to the parks. The hypotheses for the formula are as follows. a. The catchment of urban community parks can be dependent on the quantitative characteristics that urban community parks have substanial factors : the potential residential population of the proximate community to a park, park visitor's day and mean usetime per year. b. The distance to the urban park is a decided variable which can be percieved quantitatively by the researchers among the exogenous variables concerned with the mean usetime of the urban community park. The data for the variables were collected from the statistics, and the surveys for 9 parks of 4cities(Seoul, Chong-ju, Su-Won, Chon-an) in Korea, which were divided into on-site samples and off-site ones in 1991. The data were collected by questionaire surveys. A total of 548 questionaires of off-site surveys were completed by the residents in the enticing area of the parks. A total of 1053 questionaires of on-site surveys were completed by the visitors of the parks. The research could attempt to derive a formula, which was concerned with the reach of the catchment of urban community parks and the reached distance to the parks. It is testified(R2>0.8) that the numbers of mean usetime per year should be related with the reached distance from a visitor's house to a proximate park. The formula is analogized with an exponential function: {{{{ Mean Usetime per year=f(x)=Ae-BK+Ce-DK ear, X is reached distance from a visitor's house to a proximate park. A,B,C and D are parameters. And, the differences of the reach of the catchment of the parks are not only testified with resulting from the differences of the exogenous variables of qualitative characteristics differences of the parks, but also divided separately into spatial ranges. This formula will be able to anticipate the visitor's numbers of a planned urban community park.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6290-6296
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• 2015

More informative ones of heuristics can help to conduct search more efficiently to obtain solution plan. However, in general, to derive highly informative heuristics from problem specifications requires lots of computational effort. To address this problem, we propose an State-Action based Planning Graph(SAPG) and Action-based heuristics for solving planning problems more efficiently. The SAPG is an extended one to be applied to can find interactions between subgoal & goal conditions from the relaxed planning graph which is a common means to get heuristics for solving the planning problems, Action-based heuristics utilizing SAPG graphs can find interactions between subgoal & goal conditions in an effective way, and then consider them to estimate the goal distance. Therefore Action-based heuristics have more information than the existing max and additive heuristics, also requires less computational effort than the existing overlap heuristics. In this pager. we present the algorithm to compute Action-based heuristics, and then explain empirical analysis to investigate the accuracy and the efficiency of the Action-based heuristics.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.815-820
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• 2010

Fuel spray characteristics of the gasoline engine injector has been studied experimentally. Wall wetting fuel stream of the 4-hole and 12-hole injectors has been tested and measured with various installation angle and port masking shapes. Spray visualization has been performed to analyze spray formation, spray angle, and penetration length. Test result shows that wall wetting is greatly influenced by the induction air flow and injector installation angle. Wall wetting amount decreased as injector installation angle decreased. Masking decreased wall wetting amount by increasing local intake-air flow velocity due to the decreased section area. Spray visualization showed that the 12-hole injector has robust performance characteristics compared with the 4-hole injector.

• Journal of Korea Multimedia Society
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• v.10 no.5
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• pp.612-622
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• 2007

As compared with wired network environment, mobile VOD service in wireless network environment is difficult to guarantee the quality of VOD service due to the limitation of the system resources. Moreover, the wireless network has small bandwidth resources and short access range so that has limitations for providing the service to a large number of mobile clients. The limited battery capacity of a mobile device becomes an obstacle to mobile clients for enjoying VOD service for a long time. Therefore, these drawbacks should be considered in developing mobile VOD applications. This paper proposes a new technique for improving QoS of mobile VOD service by jointly use of broadcasting technique, which can provide VOD service to a large number of mobile clients simultaneously, and bursty communication technique, which can reduce the power consumption of a mobile device. With having these two techniques, streaming data are divided into segments, each of which is grouped into a particular packet and then transmitted at a time in the busty communication manner. In the performance evaluation, the power consumption on WNIC of a mobile device can be reduced by over 80%, and the initial service delay can be reduced in proportion to the number of channels compared with the existing staggered broadcasting technique.