• 한국구조물진단유지관리공학회 논문집
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• 제11권5호
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• pp.181-188
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• 2007

본 연구에서는 원형강관 가새의 국부좌굴에 의한 내력감소를 배제하기 위하여, 가새의 국부좌굴 거동을 파악하고 좌굴제어 방법을 찾고자 한다. 좌굴을 제어하기 위한 방법으로, 하나는 좌굴 영역에 커버플레이트를 설치하여 좌굴을 구속함으로써 변형능력을 확보하고자 하는 것이며, 다른 하나는 가새 중앙부에 강봉과 스프링을 이용한 수축장치를 삽입하여 압축 시 좌굴의 위험을 배제하는 것이다. 본 연구의 목적은 국부좌굴을 구속하거나 배제하기 위한 좌굴제어시스템을 제안하고, 실험을 통하여 제안한 방법의 적용성을 조사, 검토하는 것이다. 또한 좌굴제어에 따른 성능향상을 정량적으로 평가하는 것이다.

• 한국컴퓨터정보학회논문지
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• 제15권12호
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• pp.117-123
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• 2010

본 논문에서는 홈 도메인에서 상이한 DRM 규격의 콘텐츠 재배포가 안전하게 이루어질 수 있도록 홈 도메인 기반의 상호 호환성을 위한 DRM 시스템을 제안하였다. DRM 규격이 다른 디바이스간의 콘텐츠 재배포에 대한 어려움을 해결함으로서, 사용자의 콘텐츠 사용상의 제약과 불편을 해소하고 동시에 콘텐츠 제작자 및 제공자의 권익을 보호할 수 있는 홈 도메인 내의 콘텐츠 재배포를 위한 DRM 시스템을 제안하였다. 사용자가 구입한 콘텐츠를 자신이 소유한 다른 디지털 디바이스에서도 자유롭게 사용할 수 있도록, 디바이스들을 하나의 홈 도메인으로 묶어 상호 호환성있는 DRM을 위한 홈 도메인을 구축했다. 이로서 엑스포트 및 임포트 디바이스 각각 HADM에 의하여 홈도메인에서 인증되면, DIM을 이용하여 엑스포트 디바이스의 콘텐츠 및 라이선스를 임포트 디바이스의 DRM 규격에 맞게 변환한 후 재패키징하여 임포트 디바이스에게 재배포할 수 있게 된다.

• 대한조선학회논문집
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• 제42권6호
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• pp.566-574
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• 2005

Reduction of a ship's rolling is the most important performance requirement for improving the safety of the crew on board and preventing damage to cargos as well as improving the comfort of the ride. A mass driving anti-rolling system (MO-ARS) might be one candidate of several systems against the ship's rolling. As the movable range of the mass on the ship is finite, the control system must include restriction on the mass position to protect the device and the ship. This restriction usually causes windup phenomenon and control performance is deteriorated seriously. Two control algorithms, anti-windup control and saturated sliding mode control, are studied in this paper. Control performance and robustness problem are checked out by numerical simulations.

• Smart Structures and Systems
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• 제15권3호
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• pp.627-643
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• 2015

Negative stiffness, previously emulated by active or semi-active control for cable vibration mitigation, is realized passively using a self-contained highly compressed spring, the negative stiffness device (NSD).The NSD installed in parallel with a viscous damper (VD) in the vicinity of cable anchorage, enables increment of damper deformation during cable vibrations and hence increases the attainable cable damping. Considering the small cable displacement at the damper location, even with the weakening device, the force provided by the NSD-VD assembly is approximately linear. Complex frequency analysis has thus been conducted to evaluate the damping effect of the assembly on the cable; the displacement-dependent negative stiffness is further accounted by numerical analysis, validating the accuracy of the linear approximation for practical ranges of cable and NSD configurations. The NSD is confirmed to be a practical and cost-effective solution to improve the modal damping of a cable provided by an external damper, especially for super-long cables where the damper location is particularly limited. Moreover, mathematically, a linear negative stiffness and viscous damping assembly has proven capability to represent active or semi-active control for simplified cable vibration analysis as reported in the literature, while in these studies only the assembly located near cable anchorage has been addressed. It is of considerable interest to understand the general characteristics of a cable with the assembly relieving the location restriction, since it is quite practical to have an active controller installed at arbitrary location along the cable span such as by hanging an active tuned mass damper. In this paper the cable frequency variations and damping evolutions with respect to the arbitrary assembly location are then evaluated and compared to those of a taut cable with a viscous damper at arbitrary location, and novel frequency shifts are observed. The characterized complex frequencies presented in this paper can be used for preliminary damping effect evaluation of an adaptive passive or semi-active or active device for cable vibration control.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4946-4960
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• 2020

In a device-to-device (D2D) underlaid cellular network, there exist two types of co-channel interference. One type is inter-layer interference caused by spectrum reuse between D2D transmitters and cellular users (CUEs). Another type is intra-layer interference caused by spectrum sharing among D2D pairs. To mitigate the inter-layer interference, we first derive the interference limited area (ILA) to protect the coverage probability of cellular users by modeling D2D users' location as a Poisson point process, where a D2D transmitter is allowed to reuse the spectrum of the CUE only if the D2D transmitter is outside the ILA of the CUE. To coordinate the intra-layer interference, the spectrum sharing criterion of D2D pairs is derived based on the (signal-to-interference ratio) SIR requirement of D2D communication. Based on this criterion, D2D pairs are allowed to share the spectrum when one D2D pair is far from another sufficiently. Furthermore, to maximize the energy efficiency of the system, a resource allocation scheme is proposed according to weighted graph coloring theory and the proposed ILA restriction. Simulation results show that our proposed scheme provides significant performance gains over the conventional scheme and the random allocation scheme.

• 대한물리치료과학회지
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• 제10권2호
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• pp.62-72
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• 2003

The purpose of this study is to prove the efficacy of the Kaltenborn-Evjenth Orthopedic Manipulative Therapy and the Conventional Physical Therapy that influence changes in pain and range of motion when those therapies are applied to patients with temporomandibular pint movement restriction. The subjects of the study were 30 randomly selected patients who had been diagnosed with temporomandibular pint movement restriction and had endured pain for more than two weeks. These patients had visited one of three hospitals in Pyongchon 00 Hospital. The subjects were divided into two groups with 15 patients each. The Kaltenborn-Evjenth Orthopedic Manipulative Therapy was applied to one group and the Conventional Physical Therapy was applied to the other group, once a day for three days. Then, the pain perception degree was measured by using the Visual Analogue Scale(VAS) and a digital device(Absolute Digimatic) measured the range of motion for each group. The average and standard errors were calculated for each measured items and a paired t-test was used for identifying significance in the differences in the pain perception degree and the range of motion between the two groups according to therapy. The significant level was set as ${\alpha}=0.05$. The changes in the pain perception degree were statistically significant in both groups; however, the group that received Kaltenborn-Evjenth Orthopedic Manipulative Therapy(KE-Group) showed more significant changes in a decrease in the pain perception degree than did the group that received the Conventional Physical Therapy(CPT-Group). Both groups showed significant results regarding changes in the range of motion: however, the KE-Group showed more of a significant difference in the average of the range of motion than did the CPT-Group(p<0.001). Comparing the changes in the range of motion between the two groups, the KE-Group showed a significant result which means that the KE-Group had a higher therapy effect than did the CPT-Group(p<0.05). Based on the results of this study, we found that the Kaltenborn-Evjenth Orthopedic Manipulative Therapy decreased pain and increased the range of motion. With such findings, we expect that the Kartenborn-Evjenth Orthopedic Manipulative Therapy can be used as an effective treatment method for patients with tempomrnandibular pint movement restriction and that the treatment period can be reduced with this therapy as well.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• 한국컴퓨터정보학회논문지
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• 제11권1호
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• pp.243-250
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• 2006

모바일 단말기 장치가 발전하면서 컴퓨터로만 할 수 있었던 게임, 인터넷, 금융 서비스 등을 이동 단말기를 이용하여 처리할 수 있다. 본 논문에서는 펜티엄급 PC에서 유행하던 게임을 이동 단말기에서 재생가능성 하도록 재구성하고, 자동화 가능한 재구성 요소를 정리하여 아바타 변환기로 개발하고자 한다. 즉, 기존의 자원을 최대한 재활용하여 이동 단말기용 컨텐츠 개발 속도를 향상시킬 수 있는 방법을 제안하고자 한다. 플랫폼의 제약사항을 고려하여 기존의 컴퓨터의 아키텍처를 모바일 플랫폼에서 동작 가능한 로직과 리소스로 구분하여 변환하는 동작이 아바타 변환기의 주 기능이다. 이동 통신 사업자의 플랫폼 종류에 따른 다수의 컨텐츠 개발에 공용의 로직과 리소스를 변환함으로써 개발 속도를 향상시킬 수 있다.

• 한국정보통신학회논문지
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• 제11권12호
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• pp.2298-2305
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• 2007

최근 임베디드 시스템에 대한 많은 연구들이 진행 중이다. 임베디드 시스템은 점점 소형화 추세로 가고 있다. DOM(Disk On Module)저장장치는 공간에 제한이 있는 응용프로그램이나 모바일 등의 기기에 사용할 수 있다. 본 논문에서는 DOM(Disk On Module) 메모리를 사용하여, 리눅스 기반의 커널을 탑재하고, DOM 메모리 만으로 시스템이 구동될 수 있도록 한다. DOM(Disk On Module) 메모리의 용량 제한으로 인하여 소형 운영체제가 필수적이다. 이를 위해 본 논문은 기존의 리눅스 운영체제를 DOM 환경에 적합하도록 경량화시켜서 설계하였다. 리눅스 운영체제를 경량화한 후, DOM(Disk On module)에 부트 로더의 한 종류인 LILO를 설치하여 DOM(Disk On module)메모리 상에서 새롭게 설계된 경량 리눅스 운영체제가 일반 리눅스 운영체제처럼 부팅될 수 있게 만들어 준다. 본 논문은 일반 리눅스 PC와 성능을 비교하는 실험을 수행하였다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (A)
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• pp.676-678
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• 2002

In this work, we present the novel scheduling algorithm of the multimedia data retrieval for the mobile disk drive. Our algorithm is focused on minimizing the power consumption involved in data retrieval from the local disk drive. The prime commodity in mobile devices is the electricity. Strict restriction on power consumption requirement of the mobile device put unique demand in designing of its hardware and software components. State of the art disk based storage subsystem becomes small enough to be embedded in handhold devices. It delivers abundant storage capacity and portability. However, it is never be trivial to integrate small hard disk or optical disk drive in handhold devices due to its excessive power consumption. Our algorithm ARM in this article generates the optimal schedule of retrieving data blocks from the mobile disk drive while guaranteeing continuous playback of multimedia data.