• 한국광학회지
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• 제25권4호
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• pp.221-224
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• 2014

고출력 LED 소자의 활용이 많아지면서, 온도상승 문제를 극복하고 신뢰성을 향상해야 하는 요구가 높아짐에 따라 광원 패키지의 방열이 매우 중요해졌다. 패키지에 칩을 접합하는 열전달 물질(TIM, Thermal Interface Material)은 열전도도가 높은 물질과 폴리머를 혼합하여 재료 자체의 열전달 특성을 향상시키는 방안이 사용되어 왔으나, 실제 패키지의 열 특성은 칩 부착계면의 높은 열저항으로 인해 기대에 미치지 못하고 있다. 본 연구는 diamond 분말과 epoxy의 혼합으로 열 특성을 개선함에 있어서, 과산화수소를 적용하면서도 기포를 효율적으로 제거하여, 각 계면의 친화성을 높이고 전체 점도를 낮추어 diamond 분말의 분산을 촉진하고, 결과적으로 대부분의 경우에 전체 열 저항을 약 30% 이상 개선하였다.

• 우주기술과 응용
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• 제4권1호
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• pp.74-85
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• 2024

기존의 위성-지상 간 정보 전달에 사용하던 전파 통신의 한계가 가시화됨에 따라, 이를 광학 레이저 통신으로 극복하고자 전세계에서 다양한 실험이 이루어지고 있다. 본 논문에서는 인공위성에서 레이저 송출을 담당하는 광통신 터미널(optical communications terminal, OCT)과 지상에서 정보를 수신하는 광통신 지상국(optical ground station, OGS)을 자체 개발하고, 이를 이용한 자유공간 광통신(free-space optical communication, FSOC) 실험을 수행하였다. 30 mm 구경의 광통신 터미널과 250 mm 구경의 이동형 광통신 지상국 망원경, 상용 10 Gbps SFP+ 모듈과 미디어 컨버터를 이용하여, 4K HDMI(high-definition multimedia interface) 신호를 1,550 nm 파장의 레이저에 담아 송출하고 수신하는데 성공했다. 실험의 송수신거리는 각각 3, 9, 20 km이며, 각각의 거리에서 신호의 수신 세기는 +6.1, -2.8, -10.9 dBm이다. 4K HDMI 영상은 끊김 없이 10분 이상 지속됨을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1394-1400
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• 2014

The current flowing through the overhead transmission lines causes induced voltage on the communication lines, which can be prevented by calculating the induced voltage at the planning stage for overhead transmission line installment through an agreement between the communication and electric power companies. The procedures to calculate the induced voltages, however, are complicated due to the variety of parameters and tower types of the overhead transmission lines. The difficulty necessitates the development of a simulator to measure the induced voltage on the communication lines. This paper presents two simulators developed for this purpose; one using the Data Base (DB) index method and the other using the Graphic User Interface (GUI) method. The simulators described in this paper have been implemented by the EMTP (Electromagnetic Transient Program).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1182-1188
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• 2011

By storing various train information in running high speed train, we can analyze the cause of train accident efficiently. we have developed the smart and high available control method to control and manage the hardware modules. The hardware modules for event recorder consist CPU, Digital Input and Output, Pulse Input, Communication, Control Panel and Crash Protected Memory. The real time operation system is used to totally control and manage the various hardware modules. The main function of control method is collection of train information, calculation of train speed, interface with other on-board control system, storing and retrieving train information, and communication with Control Panel. In Control Panel, it displays the current train speed and the status of event recorder effectively. Also user interface is provided in Control Panel.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.753-759
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• 2006

햅틱인터페이스 기술을 이용하면 가상물체의 형태를 만져보고 느껴볼 수 있다. 물체마다 다른 수학적 마찰력 모델을 적용하여 실감있는 마찰력 표현도 가능하다. 그러나 각 물체에 해당하는 마찰력 모델을 선정하는 것과 적절한 마찰계수 등을 반복적 실험을 통하여 알아내는 것은 쉽지 않다. 실제 물체의 마찰력이 알려진 마찰력 모델과 다르다면 수학적 모델로 표현할 수 없는 경우도 있다. 본 논문에서는 신경회로망 학습을 이용하여 마찰력 모델의 선택이나 마찰계수 등을 정하는 과정 없이 실제 물체의 마찰력을 표현하는 방법을 제시하고 있다. 상용 햅틱인터페이스 장치인 PHANToM 2 대를 이용하여 마찰력 획득 시스템을 구성하고 고무판, 종이 등의 물체 표면에서의 속도와 물체에 작용하는 힘을 획득하여 가공한 데이터를 입력 및 출력으로 갖는 신경회로망을 통해 학습시킨 후 OpenGL로 구현한 가상물체에 적용하여 보았다. Force/Torque 센서를 사용하지 못한 일부 문제가 있었으나 예상보다 사실적인 마찰력을 표현할 수 있었다.

• ETRI Journal
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• 제30권1호
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• pp.141-151
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• 2008

In this paper, we introduce a new verification platform with ARM- and DSP-based multiprocessor architecture. Its simple communication interface with a crossbar switch architecture is suitable for a heterogeneous multiprocessor platform. The platform is used to verify the function and performance of a DVB-T baseband receiver using hardware and software partitioning techniques with a seamless hardware/software co-verification tool. We present a dual-processor platform with an ARM926 and a Teak DSP, but it cannot satisfy the standard specification of EN 300 744 of DVB-T ETSI. Therefore, we propose a new multiprocessor strategy with an ARM926 and three Teak DSPs synchronized at 166 MHz to satisfy the required specification of DVB-T.

• 전자공학회논문지S
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• 제34S권7호
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• pp.9-18
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• 1997

In this paper, we implemented the communication module in the Telephone Network Access Subsystem(TNAS) of the Advanced Communications Processing System(ACPS). We defined some kinds of communication tasks and related resources like several queues which are executed in real-time operating system, and implemented the procedures for processing the user information. Through traffic modeling and simulation, the performance of the Service Processing board Assembly(SPA) is evaluated in the aspets of system utilization and buffer size. The ACPS should accommodate various public networks such as public switch telephone network, packet switchen data network, frame realy netork, and ATM network. The communications module proposed in this paper could be used inthe interface beween the SPA and the High Speed Network Adaptor of other network interface subsystems.

• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.27-36
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• 2020

The popularization of smartphones allows people to instantly get the information that they want, through mobile apps, including financial services, movies and public transportation reservations, games and shopping. Furthermore, leisure activities through overseas travel are increasing due to the improvement of the living standards of people. These increases in overseas travel and the use of mobile apps lead to the increased use of mobile travel apps when booking tour packages. Although there are many studies on the usability assessment and user interface improvement for mobile apps, studies on the usability assessment for mobile travel apps are limited. We tested the usability for mobile travel apps to present some suggestions for improvements so that anyone can purchase travel packages easily and simply. We selected the top three mobile travel apps on Rankey.com that have different UIs. The heuristic method was used to evaluate usability. We present a better UI to allow users to use the app functions more easily by analyzing user interaction, ease of learning, readability, efficiency, and satisfaction for the entire use.

• Journal of electromagnetic engineering and science
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• 제10권2호
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• pp.45-49
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• 2010

This paper presents an analytical formulation of the numerical reflection coefficient of the ID-FDTD scheme at the planar dielectric boundary for a TM wave incidence. The reflection coefficient is formulated in an approximate manner, and the accuracy of this method is numerically verified. The effective dielectric constant for a grid on the interface is obtained, and then reduced to that of the Yee scheme for a small cell size.

• 한국멀티미디어학회논문지
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• 제15권4호
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• pp.501-507
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• 2012

Human body motion is a non-verbal part for interaction or movement that can be used to involves real world and virtual world. In this paper, we explain a study on natural user interface (NUI) in human hand motion recognition using RGB color information and depth information by Kinect camera from Microsoft Corporation. To achieve the goal, hand tracking and gesture recognition have no major dependencies of the work environment, lighting or users' skin color, libraries of particular use for natural interaction and Kinect device, which serves to provide RGB images of the environment and the depth map of the scene were used. An improved Camshift tracking algorithm is used to tracking hand motion, the experimental results show out it has better performance than Camshift algorithm, and it has higher stability and accuracy as well.