• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.35-38
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• 2005

본 논문은 모바일 클라이언트-서버(Mobile Client-Server) 환경에서 모바일 데이터베이스 시스템 특성상 가질 수 있는 무선 네트워크의 약한 연결성 및 접속성 단절로 인한 데이터베이스 비축(Database Hoarding)과 관련된 문제, 공유 데이터(Shared Data)의 일관성(Consistency) 유지 문제, 그리고 로그(Log) 최적화 문제를 해결하기 위한 모바일 질의 처리 시스템(MQPS : Mobile Query Processing System)을 포함하는 새로운 모바일 클라이언트-서버 시스템을 제안하는데 목적이 있다.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.236-240
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• 2008

People use diary or photograph for recall-ing their memory in order to satisfy their desires for recording their lives. If the experienced events are organized to a story, S/he can share her/his experience with others, and recall her/his significant events easily. In this paper, we propose a method that generates a story with Petri net and user contexts collected from mobile device. Here, we use Petri-net as a representation method that links human activities or experience causally. It is appropriate solution for modeling parallel events in real world, and for representing non-linear story line. In order to show the usefulness of the proposed method, we show an example of generating a story of user's experience with user contexts from mobile device and evaluate them.

• Journal of Communications and Networks
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• v.16 no.5
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• pp.568-577
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• 2014

We consider a mobile content delivery network (mCDN) in which special mobile devices designated as caching servers (caching-server device: CSD) can provide mobile stations with popular contents on demand via device-to-device (D2D) communication links. On the assumption that mobile CSD's are randomly distributed by a Poisson point process (PPP), an optimization problem is formulated to determine the probability of storing the individual content in each server in a manner that minimizes the average caching failure rate. Further, we present a low-complexity search algorithm, optimum dual-solution searching algorithm (ODSA), for solving this optimization problem. We demonstrate that the proposed ODSA takes fewer iterations, on the order of O(log N) searches, for caching N contents in the system to find the optimal solution, as compared to the number of iterations in the conventional subgradient method, with an acceptable accuracy in practice. Furthermore, we identify the important characteristics of the optimal caching policies in the mobile environment that would serve as a useful aid in designing the mCDN.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06a
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• pp.97-98
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• 2007

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.357-362
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• 2009

We propose a method to recommend most likely people to call based on call log of mobile phone user. Call logs of an user can reflect calling pattern of the user include regular calling behavior. When user got a list of people to call with a click of 'send' button on the phone, the time and effort to search a person with several typing or to select a person from the list can be definitely reduced. This paper presents the design process of an algorithm to find most likely people to call at a certain moment and the verification process with recorded call log and Experience Sampling Method(ESM) on mobile phone.

• The Journal of Society for e-Business Studies
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• v.21 no.4
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• pp.151-159
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• 2016

The user interface is an important factor in providing efficient services to application users. In particular, mobile applications that can be executed anytime and anywhere have a higher priority of usability than applications in other domains.Previous studies have used prototype and storyboard methods to improve the usability of applications. However, this approach has limitations in continuously identifying and improving the usability problems of a particular application. Therefore, in this paper, we propose a usability analysis method using touch gesture data. It could identify and improve the UI / UX problem of the application continuously by grasping the intention of the user after the application is distributed.

• Analytical Science and Technology
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• v.8 no.4
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• pp.519-527
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• 1995

The retention mechanism of Ni(II)-${\alpha}$-isonitroso-${\beta}$-diketone imine chelates in reversed-phase HPLC has been studied by examining the effect of temperature, mobile phase composition in acetonitrile-water mixture, and molecular structure on retention. The empirical retention equation was investigated to evaluate the properties of S (hydrophilic index). The value of the S index of the Ni(II) chelates decrease with the increasing column temperature and a linear relationship between S and log $k{_w}^{\prime}$ has been found. The results showed that the S index is influenced by the interaction between Ni(II) chelates and mobile phase. Molecular properties, van der Waals molar volume, polarizability and dipole moment, of the Ni(II) chelates were calculated by Cerius 2 program and the calculations were performed at Universal Force Field (UFF) model. The S value and log $k{_w}^{\prime}$ increase with decreasing the dipole moment of Ni(II) chelates.

• Proceedings of the Korean Society of Computer Information Conference
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• 2010.07a
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• pp.311-314
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• 2010

예전부터 IT 기술을 이용한 장애인의 복지 증진을 위한 많은 연구들이 진행되고 있다. 최근에는 거리에 설치된 수많은 모바일 센서들을 활용하여 라이프 로그를 저장하고 네트워크를 통하여 서버에 전송함으로써 로그를 저장한 후, 이러한 라이프 로그를 분석함으로써 해당 사용자가 위험에 노출되어 있는 지를 판단 할 수 있게 되는 시스템이 많이 제안되고 있다. 특히 장애인의 경우 위험에 노출되기 쉬우며 매번 보조자들이 함께 다녀야 한다는 부담 때문에 외출을 두려워하는 경향이 있다. 따라서 이러한 부담감을 덜어주어야 심리적으로도 육체적으로도 더 나은 삶을 살아갈 수 있게 유도할 수 있을 것이다. 본 연구는 이러한 심리적 부담감을 덜어주기 위한 방법으로 장애인의 라이프 로그를 기록하고 분석할 수 있는 시스템을 제안한다.

• Journal of Korea Technology Innovation Society
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• v.14 no.3
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• pp.622-646
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• 2011

This paper analyses the effects of mobile telecommunications market's interconnection charge on consumer welfare between 2000 and 2010 by estimating price elasticity of demand with using log linear model and augmented Alexander et al(2000)'s model. The results show that consumer welfare is about 6 trillion won in 2009 and an upward trend. In the 2nd analysis, the decline in interconnection charge raise consumer welfare but, asymmetric interconnection and current TD-BU LRIC system have negative(-) relation with consumer welfare. Hence we need to revise interconnection policy frame.

• Journal of Convergence Society for SMB
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• v.5 no.3
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• pp.21-26
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• 2015

As mobile contents grow up, In App Billing is brisk at applications including mobile contents. But some of users don't pay and use charged content for free to use cheating payment module or hacking through applications. Call this bypass payment. Applications, helping bypass, are Freedom, IAP Cracker, and DNS server suggested by the hacker named Borodin. In case of mobile game, Despite sell a lot of charged content but income is different revenue in sales log with real profits. Because of users using bypass payment application. Management plan to bypass payment are checking OrderID, encrypting public key and verifying receipt.