• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.475-482
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• 2014

In this paper, we have implemented mobile based smart greenhouse system that can grasp and control the situation for greenhouse from distance. Using existing web based greenhouse system is controlled in real time, but it has a drawback used in limited place. To solve this problem, we have emphasized usability of smart greenhouse system by using mobile device. By using mobile devices (smartphones - the Android based) software we have to raise the comfort and productivity for grasping and controling the situation for greenhouse from distance.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.562-566
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• 2011

As telecommunication technologies in telemedicine services are developed, the expeditious development of wireless and mobile networks has stimulated wide applications of mobile electronic healthcare systems. However, security is an essential system requirement since many patients have privacy concerns when it comes to releasing their personal information over the open wireless channels. Due to the invisible feature of mobile signals, hackers have easier access to hospital networks than wired network systems. This may result in several security incidents unless security protocols are well prepared. In this paper, we analyzed authentication and authorization procedures for healthcare system architecture to apply secure M-health systems in the hospital environment. From the analyses, we estimate optimal requirements as a countermeasure to its vulnerabilities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5673-5691
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• 2019

Information centric mobile network can significantly improve the data retrieving efficiency by caching contents at mobile edge. However, the cache pollution attack can affect the data obtaining process severely by requiring unpopular contents deliberately. To tackle the problem, we design an algorithm of mitigating cache pollution attacks in information centric mobile network. Particularly, the content popularity distribution statistic is proposed to detect abnormal behavior. Then a probabilistic caching strategy based on abnormal behavior is applied to dynamically maintain the steady-state distribution for content visiting probability and achieve the purpose of defense. The experimental results show that the proposed scheme can achieve higher request hit ratio and smaller latency for false locality content pollution attack than the CacheShield approach and the baseline approach where no mitigation approach is applied.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.358-361
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• 2015

BYOD(Bring your own device) 환경에서는 개인의 스마트 기기를 이용하여 회사 시스템을 이용하는 것으로, 개인의 단말을 업무에 이용하는 만큼 사원의 개인정보, 고객의 개인정보, 신규 사업 아이템, 상품의 거래내역, 계좌번호 등 유출시 막대한 손해를 발생시키는 사내 정보 유출에 대한 문제가 발생 가능하다. 회사 시스템을 관리하기 위해 개개인이 사용하는 다양한 종류의 단말에 맞는 설정이 필요함으로 즉각적인 대응이 어렵다. 때문에 위 같은 문제를 해결하고자 삼성이 개발한 듀얼 OS 구조의 KNOX가 제안되었으나, 특정 단말과 OS에 의존적이어서 다양한 종류의 단말에 적용하기 위해서는 지속적 개발이 필요한 단점이 있다. 다른 방법으로 MDM(Mobile Device Management) 시스템을 제안하였지만 새로운 모바일 단말에 대한 즉각적인 대응이 힘들며, 유지보수에 많은 시간과 투자가 필요한 단점이 있다. 따라서 본 논문에서는 단말에 의존적이지 않으면서, 기업의 정보를 보호하기 위하여 클라우드 기반 정보 유출 방지 플랫폼을 설계하고 제안한다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.7
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• pp.572-575
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• 2009

In this study, we proposed WLED(White-Light Emitting Diode) driver IC for mobile applications. This IC drove WLED for mobile applications with low input voltage and high efficiency by using boost converter. The device was designed by using boost converter applied current-mode control algorithm and provided PWM(Pulse Width Modulation) & analog dimming. Designed IC consisted of bias block, drive block, control block, protection block. We confirmed this device worked well through a application PCB (Printed Circuit Board) test.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3435-3454
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• 2016

Device-to-device (D2D) communication is a potential solution to the incessant increase in data traffic on cellular networks. The greatest problem is how to control the interference between D2D users and cellular mobile users, and between D2D users themselves. This paper proposes a solution for this issue by putting the full control privilege in cellular network using the software-defined networking (SDN) concept. A software virtual switch called Open vSwitch and several components are integrated into mobile devices for data forwarding and radio resource mapping, whereas the control functions are executed in the cellular network via a SDN controller. This allows the network to assign radio resources for D2D communication directly, thus reducing interference. This solution also brings out many benefits, including resource efficiency, energy saving, topology flexibility, etc. The advantages and disadvantages of this architecture are analyzed by both a mathematical method and a simple implementation. The result shows that implementation of this solution in the next generation of cellular networks is feasible.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5614-5633
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• 2018

Mobile Edge Computing (MEC) and Wireless Power Transfer (WPT) are both recognized as promising techniques, one is for solving the resource insufficient of mobile devices and the other is for powering the mobile device. Naturally, by integrating the two techniques, task will be capable of being executed by the harvested energy which makes it possible that less intrinsic energy consumption for task execution. However, this innovative integration is facing several challenges inevitably. In this paper, we aim at prolonging the battery life of mobile device for which we need to maximize the harvested energy and minimize the consumed energy simultaneously, which is formulated as residual energy maximization (REM) problem where the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device are all considered as key factors. To this end, we jointly optimize the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device to solve the REM problem. Furthermore, we propose an efficient convex optimization and sequential unconstrained minimization technique based combining method to solve the formulated multi-constrained nonlinear optimization problem. The result shows that our joint optimization outperforms the single optimization on REM problem. Besides, the proposed algorithm is more efficiency.

• Journal of Korea Multimedia Society
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• v.19 no.12
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• pp.1936-1942
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• 2016

This paper presents a mobile color-compensating application using a RGB color compensation algorithm. The proposed application enables color vision deficiencies to differentiate images which cannot be distinguished by them. The suggested mobile application has two functions: converting images taken by camera and converting contents in the device screen. The proposed application is computationally inexpensive, since it does not require color space transformation. Simulation results show that the proposed application enables color vision deficiencies to receive information expressed by colors such as subway line maps.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.687-698
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• 2002

Together with the activation of wireless Internet, the interest for various integrated methods of the existing wired and wireless e-commerces is on the rise. For the integrated wired and wireless e-commerce, firstly, the optimized security and authentication under the radio communication environment should be decided. And also the user-friendly usage is important. In this paper, we designed and implemented wired and wireless interworking Mobile Wallet on terminal that can be used through both wired and wireless methods by developing electronic wallet module for electronic payment using MIDP (Mobile Information Device Profile) based on J2ME (Java 2 Micro Edition). The characteristics of mobile wallet implemented in this paper provide the stability through encoding/decoding payment information and on-line usage on wired/wireless environments through downloading electronic wallet. In addition, we also present safe and convenient payment method for e-commerce based on wired/wireless Internet.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.379-382
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• 2004

In this paper, it is investigated in advance about the PZT-based composition for piezoelectric vibration device. The specimens of piezoelectric ceramics are made of Columbite method. The piezoelectric vibration device by this composition is designed by ATILA(Magsoft) program used FEM(Finite Element Method). The vibration device used for mobile phone must be driven in the frequency of $130{\sim}200Hz$, so the resonant frequency of piezoelectricity must adjust driven frequency bandwidth. The result of analysis by ATILA is appeared dependant property of length, width, thickness and dummy weight about resonant frequency of the piezoelectric vibration device. The size of manufactured actuator is $28{\times}12{\times}0.3mm^3(length {\times}width{\times}thickness)$ and this is bimorph type. The test of manufactured piezoelectric vibration device measure displacement, acceleration and power dissipation. The piezoelectric vibration device has the advantage more than electro-magnetic motor, however the size of manufactured device is larger than electro-magnetic motor.