• International journal of advanced smart convergence
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• v.5 no.3
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• pp.66-71
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• 2016

Smart building gate security control system using smartphone integrated with near field communication (NFC) has become part of daily life usage these days. The technology change in replacing RF NFC device using visible light communication technology based approach growing faster in recent days. This paper propose a design and development of gate security control system using color code based user authentication ID generation as part of an intelligent access control system to control automatic door open and close. In this approach gate security access control use the recent visible light communication technology trends to transfer the user specific authentication code to door access control system using color code on smartphone screen. Using a camera in the door access control system (ACS), color codes on smartphone screens are detected and matched to the database of authenticated user to open the door automatically in gate security system. We measure the visual light communication technology efficiency as a part of the research and the experiments have revealed that more than 95% users authenticated correctly at the suggested experiment environment on gate security control system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.509-512
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• 2018

최근 미세먼지에 대한 관심이 높아지고 있으며, 미세먼지를 줄이기 위한 다양한 기술이 연구되고 있다. 본 연구에서는 기존 가솔린 이륜차의 단점을 극복하고 미세먼지 발생을 줄일 수 있는 배터리 교환식 이륜차 및 IoT 기반 지원시스템을 소개한다. 전기 이륜차에 탑재되는 IoT Edge device에서는 배터리 잔량, 배터리 ID, 위치 정보 등의 정보를 LTE-M 통신을 통해 IoT 클라우드에 전송하고, 배터리 교환이 필요한 경우 주변의 배터리 교환기 위치 및 교환 가능한 배터리 정보 전달 받을 수 있다. 현재 전기이륜차에 탑재될 IoT Edge device 및 사용자용 스마트폰앱을 개발하고 있으며, 배터리 교환기 및 클라우드 서비스 개발도 수행될 예정이다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3597-3605
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• 1999

We introduce a new satellite Conditional Access System(CAS) that a subscriber could watch a pay-TV knowing only his or her identity and password, without using a smart card. For this new system, two password-based protocols are presented which not only share a session key and authenticate each other but also download an authorization key. This system has some merits: First, compared with current systems, it reduces the amount of computations by eliminating the AK-encryption module in SMS(Subscriber Management System) and simplifying the receiver's CW-decryption process. Second, since this system does not need an expensive Card Adaptive Device(CAD), it can reduce costs. finally it provides descrambler independence allowing it to be used through any TV set-top box that includes a descrambler, unlike the current system that a descrambler is linked with a smart card.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.1
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• pp.1-9
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• 2013

Performance of smart phones has increased to conduct simple PC functions that has become essential to modern people. With the development of smart phones, not only limited inner sensors but various sensors can be connected through USB. However, there is problem that app needs to downloaded when using each sensor. In this paper, a smart phone unified app structure for USB sensor Plug&Play is presented. The structure was designed to download web pages to use various sensors in one app. Unified app communicated with the platform through ADK accessory protocol and implements structure of delivering sensor ID to the web server and downloading device driver, web page. By measurement test, it was confirmed that download time of web page in unified app was 10 times faster than original download time of original app. By managing various sensors by one app, the app is searched every time the sensor changes in which there is no need for downloading several apps.

• International Journal of Control, Automation, and Systems
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• v.3 no.3
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• pp.493-501
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• 2005

A power plant simulation tool ('PowerSim') has been developed with 10 years experience from the development of a plant simulator for efficient modeling of a power plant. PowerSim is the first developed tool in Korea for plant simulation with various plant component models, instructor station function and the Graphic Model Builder (GMB). PowerSim is composed of a graphic editor using general purpose design software, a netlist converter, component models, the scheduler, Instructor Station and an executive. The graphic editor generates a netlist that shows the connection status of the various plant components from the Simdiagram, which is drawn by Icon Drag method supported by GUI environment of the PowerSim. Netlist Converter normalizes the connection status of the components. Scheduler makes scheduling for the execution of the device models according to the netlist. Therefore, the user makes Simdiagram based on the plant Pipe and Instrument Drawing (P&ID) and inputs the plant data for automatic simulating execution. This paper introduces Graphic Model Builder (GMB), instructor station, executive and the detailed introduction of thermal-hydraulic modeling. This paper will also introduce basic ideas on how the simulation Diagram, based on netlist generated from general purpose design software, is made and how the system is organized. The developed tool has been verified through the simulation of a real power plant.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.3
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• pp.285-293
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• 1998

This paper presents an experimental study on condensing heat transfer characteristics of R-22 alternative refrigerants, R-290 and R-410a on water sources heat pump. The apparatus mainly consisted of vapor pump condenser used to the test section evaporator manual expansion valve and measuring device. Test section constructed a smoothed tube of 10.07 mm ID and 12.7mm OD with a total length 6,300 mm was horizontal double pipe counterflow condenser. The refrigerants R-22, R-290 and R-410a were cooled by a coolant circulated in a surrounding annulus. Experimental range of mass velocities was changed from about 100 to 300 kg/($m^2$.s) and inlet quality 1.0 The credibility of experimental apparatus was 6 percent between heating capacity and cooling capacity added to compressor shaft power. The condensing heat transfer coefficients were increased with increasing mass velocity. However in case of R-290 they were more increasing than those of R-410a and R-22 Comparing the heat transfer coefficient between the experimental data and other's data the Cavallini-Zecchin's data was revealed to more similar prediction of author's experimental results on the average heat transfer coefficients.

• Journal of the Korean Vacuum Society
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• v.4 no.S1
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• pp.168-173
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• 1995

$GaxIn{1_x}As$ epitaxial layers were grown by a simplified hydrode vapor phase epitaxy(VPE) method bsed on the utilization of Ga/In alloy as the source metal. The effects of a wide range of experimental variables(i.e.,inlet mole fraction of HCI, deposition temperature, Ga/In alloy composition) on the ternary composition and growth rate were investigated. Layers of $Ga_{0.47}In_{0.53}As$ lattice matched to InP were successfully grown from alloys containing 5 to 8 at.% Ga. These layers were used to produce state-of-the art p-i-n photodetectors having the following characteristics: dark current, $I_d$(-5V) = 10-20 nA: responsivity, R=0.84-0.86 A/W; dark current, Id(-5V)=10-20 nA; responsivity, R=0.84-0.86 A/W; capacitance, C=0.88-0.92 pF; breakdown voltage, $V_b$ >40V. This study demonstrated for the first time that a simplified hydride VPE process with a Ga/In alloy source is capable of producing device quality epitaxial layers.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1775-1784
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• 2002

Fingerprint recognition technology is used in many biometrics field accordingly essential feature of fingerprint image and the study is progressing. However development is not perfect in performance of the fingerprint recognition and application of the usual life. In the paper, we study various necessity of preprocessing according to algorithm and circumstances of authentication system in automatic information machine. We prove that system circumstance and optation of fingerprints image effectively is the important factor by using optical fingerprint input device and scanning the fingerprint in ID card. And then we present correct and fast computation method for improving image and feature extraction of fingerprint. Also we study effective algorithm implementation of total system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.738-745
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• 2014

Recently, mobile users continuously increase, and mobile applications also increase As mobile applications increase, the mobile users used to store sensitive and private information such as Bank information, location information, ID, password on their mobile devices. Therefore, recent malicious application targeted to mobile device instead of PC environment is increasing. In particular, since the Android is an open platform and includes security vulnerabilities, attackers prefer this environment. This paper analyzes the performance of malware detection system applying linear SVM machine learning classifier to detect Android malware application. This paper also performs feature selection in order to improve detection performance.

• ETRI Journal
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• v.39 no.2
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• pp.222-233
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• 2017

Debugging in distributed environments, such as wireless sensor networks (WSNs), which consist of sensor nodes with limited resources, is an iterative and occasionally laborious process for programmers. In sensor networks, it is not easy to find unintended bugs that arise during development and deployment, and that are due to a lack of visibility into the nodes and a dearth of effective debugging tools. Most sensor network debugging tools are not provided with effective facilities such as real-time tracing, remote debugging, or a GUI environment. In this paper, we present a hybrid debugging framework (HDF) that works on WSNs. This framework supports query-based monitoring and real-time tracing on sensor nodes. The monitoring supports commands to manage/control the deployed nodes, and provides new debug commands. To do so, we devised a debugging device called a Docking Debug-Box (D2-Box), and two program agents. In addition, we provide a scalable node monitor to enable all deployed nodes for viewing. To transmit and collect their data or information reliably, all nodes are connected using a scalable node monitor applied through the Internet. Therefore, the suggested framework in theory does not increase the network traffic for debugging on WSNs, and the traffic complexity is nearly O(1).