• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2653-2660
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• 2011

Facilities for disabled person are currently required for rolling stock and its requirements are increased. Researching and development to meet these requirements must be necessary. One of them, ramp between platform and train for wheelchair user was developed and applied in real project, the case is described as per the result. The main contents of this paper is for double leaves type wheelchair ramp development operated by manual. This ramp is fixed at floor area of interior with locking device. So operating is allowed for authorized person only. Beside of this, brief comparison with other types will be mentioned.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.45-50
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• 2018

Many of the current successful commercial recommender systems utilize collaborative filtering techniques. This technique recommends products to the active user based on product preference history of the neighbor users. Those users with similar preferences to the active user are typically named his/her neighbors. Hence, finding neighbors is critical to performance of the system. Although much effort for developing similarity measures has been devoted in the literature, there leaves a lot to be improved, especially in the aspect of handling subjectivity or vagueness in user preference ratings. This paper addresses this problem and presents a novel similarity measure using fuzzy logic for selecting neighbors. Experimental studies are conducted to reveal that the proposed measure achieved significant performance improvement.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.195-197
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• 2022

일반적으로 게임에서는 유저의 과금이나 광고 시청 등으로 수익을 내기 때문에 게임을 플레이 하는 유저의 수는 곧 그 게임의 수익으로 이어진다. 그러므로 신규 유저의 유입뿐만 아니라 기존 유저의 이탈을 막는 것 또한 매우 중요하다. 유저의 이탈은 짧은 기간 동안 게임을 플레이 한 유저인지 아니면 매우 오래 플레이하고 과금까지 하던 충성고객인지를 가리지 않고 일어난다. 본 논문은 설문을 통해 온라인과 모바일 게임에서 유저의 이탈 경험과 이탈 원인에 대해서 조사하고 이에 따른 유저의 이탈 예방과 개선 방안을 제시한다.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.129-138
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• 2008

This study was carried out to examine the growth condition of Chionanthus retusa, roadside tree in Cheongyechon (CGC) and to investigate the relationship soil characteristics and tree vitality and chlorophyll contents of it. Growth condition of tree (condition of flower, leaves and branch, % of flowering, height, diameter at breast height, width, vitality and chlorophyll contents) and physiochemical relation item (pH, organic matter, K, Mg, Na, Ca, P) were investigated. The result are as follows : 1. The growth condition of flower, leaves and branch in the left side of CGC is better than the right side since the quantity of sunshine of left side of CGC is much more than the right side. 2. The average pH was alkaline. P and organic contents were much lower than the standards. 3. Tree vitality and chlorophyll contents were bad where were high user density and high buildings, such as 1, 2 area near Jong-gak and jongro 3 ga. Among the physiochemical factors of soil which affect tree vitality, K and P were found to be the main factors. Therefore, in order to improve the growth environment of roadside tree in CGC, it is needed to do periodical soil fertilizing and improve physical characteristics of soil such as, permeability and porosity by soil conditioner.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.637-646
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• 2013

In order to model a variety of natural trees that are appropriate to outdoor terrains consisting of multiple trees, this study proposes a modeling method of new growth rules(based on the convolution sums of divisor functions). Basically, this method uses an existing growth-volume based algorithm for efficient management of the branches and leaves that constitute a tree, as well as natural propagation of branches. The main features of this paper is to introduce the theory of convolution sums of divisor functions that is naturally expressed the growth or fate of branches and leaves at each growth step. Based on this, a method of modeling various tree is proposed to minimize user control through a number of divisor functions having generalized generation functions and modification of the growth rule. This modeling method is characterized by its consideration of both branches and leaves as well as its advantage of having a greater effect on the construction of an outdoor terrain composed of multiple trees. Natural and varied tree model creation through the proposed method was conducted, and using this, the possibility of constructing a wide nature terrain and the efficiency of the process for configuring multiple trees were evaluated experimentally.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1058-1065
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• 2008

In the Internet, as computer resource is developed, multimedia data request being increase more and more. It is effective way that process both high capacity-data and real-time data. Overlay Multicast is an effective method for efficient utilization of system resources and network bandwidth without using hardware customization. Overlay Multicast is an effective method for multimedia data service to multi-users. Multicast tree reconstruction is required when a non-leaf host leaves or fails. In this paper, relay-frame interval is selected as revealed network-state with jitter. In our proposal, multi-user service control algorithm gives a delay effect in multimedia request time. The simulation results show that our proposal takes shorter period of time than the other algorithms to reconstruct a similar tree and that it is a more effective way to deal with a lot of nodes that have lost their multi-user nodes.

• Journal of IKEEE
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• v.22 no.2
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• pp.250-257
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• 2018

In this paper, a smart bus system that automates public bus traffic payment by applying beacon and computer vision and provides bus route information, real-time location information, getting off alarm is proposed. By using the beacon to recognize busses near the stop and to board the bus to be boarded, this system automatically processes the payment when boarding by using the distance from the beacon and the information provided by the beacon and the face comparison. After the payment processing, the system provides the route information of the boarded bus and the real-time bus location information to the user, and when the user sets an alarm using these informations, the alarm is activated when the bus leaves the bus stop.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3514-3522
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• 1999

While the method of information collection and visual interface technique have been researched actively on web information retrieval, a study on structured modeling for effective classification of a wide collective information leaves to be desired. In this paper, we represent information feature based on structured information model. It aims at carrying out effectively the user's retrieval environment through visualization technique with analyzing the information feature. We propose a information classification method using Facet units and we construct the object model, table model, SQL code to define the relation of the information, and represent the information feature based on a wide range of views. After users gain a better global understanding of the information feature, retrieve more easily through their information. Conventional information retrieval is user-oriented to be what user want, but proposed technique it data-oriented which helps users to understand what exist in database by showing information feature.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.689-697
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• 2004

Rapid advances in mobile computing and the availability of wireless communications will soon provide mobile users with the ability to access data regardless of the location of the user or of the data. SRA(Static Replica Allocation) that is traditional scheme has been used for the replication method on the server. This replicates the data on the replica server after a moving host has been transferred to the cell. This strategy is simple and can easily relocate data. However, if a mobile user does not exist in the cell, the replicated data can be deleted in order to maintain data consistency. In addition to, if the mobile host leaves from replicated cell, it is difficult to access data in terms of replication route. Therefore, this paper proposes a new method of relocation based on data consistency strategy called USRAC(User Selection Replica Allocation based on Consistency) and also analyzes access cost according to the moving rate of mobile users, according to the access rate of mobile hosts, and according to the number of cells of mobile users and mobile hosts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.6
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• pp.3254-3272
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• 2017

With the development of wireless access technologies and the popularity of mobile intelligent terminals, cloud computing is expected to expand to mobile environments. Attribute-based encryption, widely applied in cloud computing, incurs massive computational cost during the encryption and decryption phases. The computational cost grows with the complexity of the access policy. This disadvantage becomes more serious for mobile devices because they have limited resources. To address this problem, we present an efficient verifiable outsourced scheme based on the bilinear group of prime order. The scheme is called the verifiable outsourced computation ciphertext-policy attribute-based encryption scheme (VOC-CP-ABE), and it provides a way to outsource intensive computing tasks during encryption and decryption phases to CSP without revealing the private information and leaves only marginal computation to the user. At the same time, the outsourced computation can be verified by two hash functions. Then, the formal security proofs of its (selective) CPA security and verifiability are provided. Finally, we discuss the performance of the proposed scheme with comparisons to several related works.