• IEIE Transactions on Smart Processing and Computing
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• 제5권4호
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• pp.274-282
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• 2016

This paper proposes code optimization techniques to reduce energy consumption of complex multimedia applications in a hybrid memory system with volatile dynamic random access memory (DRAM) and non-volatile spin-transfer torque magnetoresistive RAM (STT-MRAM). The proposed approach analyzes read/write operations for variables in an application. Based on the profile, variables with a high read operation are allocated to STT-MRAM, and variables with a high write operation are allocated to DRAM to reduce energy consumption. In this paper, to optimize code for real-life complicated applications, we develop a profiler, a code modifier, and compiler/link scripts. The proposed techniques are applied to a Fast Forward Motion Picture Experts Group (FFmpeg) application. The experiment reduces energy consumption by up to 22%.

• 한국수산과학회지
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• 제49권3호
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• pp.393-403
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• 2016

A steady, strong southward flow was observed in the lower layer beneath the Tsushima Warm Current in the deepest trough of the Korea Strait. Known as the Korea Strait Bottom Cold Water (KSBCW), this bottom current had a mean velocity of 24 cm/s and temperatures below 8–10℃. The direction of the bottom current was highly stable due to the topographic effects of the elongated trough. To determine the path of the southward bottom current, ADCP (Acoustic Doppler Current Profiler) data from 14 stations between 1999 and 2005 were examined. Persistent southward flows with average speeds of 4–10 cm/s were observed at only three places to the north of the strait where the bottom depths were 100–124 m. The collected data suggest a possible course of the southward bottom current along the southeast Korean coast before entering the deep trough of the Strait.

• 한국관개배수논문집
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• 제17권2호
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• pp.49-56
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• 2010

This study was carried out to survey for morphological change of lower tidal flat near Byunsan-Gosapo beach using single-beam echosounder and sound velocity profiler. Since October 2009 in the center of the region, the erosion occurred about 10~50cm, while either side of the study area is little change. Erosion occurred at the beach, each beach area in the southwest area rather than further accumulation occurred sandbank formed. Observed in the study area near the center of the erosion is the result of ongoing changes that were temporarily due to seasonal changes is not clear. However, the northwestward waves were expected to be a major source of erosion. Because of this, continue to observe the terrain and the local ocean circulation studies will be required.

• 건설관리
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• 제4권1호
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• pp.48-54
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• 2003

An automated system for scanning and characterizing unbound aggregates, called the 'Laser-based Aggregate Scanning System'(LASS), has been developed at the University of Texas at Austin. The system uses a laser profiler to acquire and analyze true three-dimensional data on aggregate particles to measure various morphological properties. Tests have demonstrated that the system can rapidly and accurately measure grain size distribution and dimensional ratios, and can objectively quantify particle shape, angularity, and texture in a size invariant manner. In its present state of development, the LASS machine is a first-generation, laboratory testing device. With additional development, this technology is expected to provide high-quality, detailed information for laboratory and on-line quality control during aggregate production.

• 한국표면공학회지
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• 제35권6호
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• pp.377-382
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• 2002

We investigated the appropriate wet cleaning process for Co-Ti-Si compounds formed on top of cobalt disilicide made from Co/Ti deposition and two rapid thermal annealing (RTA). We employed three wet cleaning processes, WP1 ($H_2$SO$_4$ etchant), WP2 ($NH_4$OH etchant), and WP3 which execute sequentially WP1 and WP2 after the first RTA. All samples were cleaned with BOE etchant after the second RTA. We characterized the sheet resistance with process steps by a four-point probe, the microstructure evolution by a cross detail sectional transmission electron microscope, a Auger depth profiler, and a X-ray diffractometer (XRD). We confirmed WP3 wet cleaning process were the most suitable to remove CoTiSi layer selectively.

• Tribology and Lubricants
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• 제25권4호
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• pp.250-255
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• 2009

Oxidation characteristics of Zirlo and Zircaloy-4 tubes, which are widely used as nuclear power fuel cladding, are studied in steam environment up to $1200^{\circ}C$. Oxidation resistances are compared in terms of the mass increase due to the absorption of oxygen. The evolution of microscopic structure accompanied with the oxidation process is investigated. Also, the influence of oxidation on the fretting wear characteristics of the tubes is studied. Piezo-electrically actuated rig is employed to fret the tubes with cross-contacting arrangement. Wear scar is observed and measured, by using microscopes and a 3D-profiler. The results of fretting wear are quantified in terms of scar size, wear volume and wear coefficient, and compared for the three different tube materials of oxidated Zirlo, virgin Zirlo and Zircaloy-4.

• 한국정밀공학회지
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• 제15권3호
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• pp.99-106
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• 1998

Recently, scientists introduced a new type of microscope capable of investigating nonconducting surfaces in an atomic scale, which is called AFM (Atomic Force Microscope). It was an innovative attempt to overcome the limitation of STM (Scanning Tunnelling Microscope) which has been able to obtain the image of conducting surfaces. Surfaces of samples are imaged with atomic resolution. The AFM is an imaging tool or a profiler with unprecedented 3-D resolution for various surface types. The AFM technology, however, leaves a lot of room for improvement due to its delicate and fragile probing mechanism. One of the room for improvements is gap control between probe tip and sample surface. Distance between probe tip and sample surface must be kept in below one Angtrom in order to measure the sample surface in Angstrom resolution. In this paper, AFM system modeling, experimental system identification and control scheme based on system identification are performed and finally sample surface is measured by home-built AFM with such a control scheme.

• 소성∙가공
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• 제17권2호
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• pp.91-96
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• 2008

The governing parameters affecting the fatigue properties have been investigated experimentally in the high carbon steel wires with 0.94 wt.%C. In order to find the crucial factors, the advanced analysis techniques such as optical 3-D profiler, focused ion beam(FIB) and transmission electron microscope(TEM) were used. The two-type steel wires with different drawing strain were fabricated. The fatigue properties were measured by hunter rotating beam tester, specially designed for thin-sized steel wires. It was found that the fatigue properties of the steel wires with high drawing strain was higher than that with other wires because of low residual stress and high adhesion condition of brass coating layer.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.365-370
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• 2004

본 연구에서는 ADCP를 이용하여 수집된 3차원적 하천 유속 자료를 기기 특성상 오류, 운용상 오류 등을 고려하여 검토하였으며, 원시 자료의 편차를 보정하는 공간평균기법을 적용하여 필터링함으로써 유속 자료를 추출하였다 공간평균기법으로 추출된 자료는 원시 자료에 비해 유속 편차가 감소되어 매끄러운 유속 분포를 보여주었을 뿐만 아니라 원시 자료에 의한 유량 계산 결과와 거의 일치하여 유속 분포를 적절하게 필터링하는 것으로 파악되었다. 또한 공간평균된 유속 자료를 이용하여 하천의 흐름장을 일목요언하게 제시할 수 있는 평면적 유속 벡터와 단면상 유속 벡터를 제시하였다. 차후 다른 유속계를 이용한 결과와 적절히 비교된다면 공간평균된 자료는 원시 자료에 비해 보다 유용할 것으로 예상되며 하천 흐름 해석 및 수치 모의에 기초 자료로 이용될 수 있을 것으로 기대된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.916-920
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• 2007

ADCP(Acoustic Doppler Current Profiler)는 유수의 흐름을 방해하지 않으면서 물 속으로 일정 주파수의 초음파를 전송하고, 부유하는 입자들에 의해 산란되어 돌아오는 반향을 수집, 도플러효과를 이용하여 유속을 측정하는 장비이다. ADCP는 하천을 횡단하면서 순간적인 유속을 측정하므로 시간평균한 평균유속과의 차이가 발생하지만 1초에 1회 이상의 빠른 속도로 연직유속분포를 수집하면서 이를 공간적으로 평균함으로써 순간유속이 갖는 변동성을 완화시키는 특징을 갖는다. 본 연구에서는 ADCP를 활용하여 사행하천에서 수평방향 2차원 유속분포를 측정하고자 하였다. 만곡부가 교호적으로 나타나는 사행하천의 흐름구조는 매우 복잡하다. 특히 주 흐름의 수직인 단면에 나선형의 2차류가 관찰되는데, 이는 원심력과 횡방향의 수면경사 및 난류의 상호작용으로 발생된다. 주 흐름의 유속과 다른 분포를 나타낸다. 본 연구에서는 이찬주 등(2005)이 제시한 공간평균기법과 이동경로 수정을 통하여 측선별 2차원 유속분포를 측정하여 기 개발된 RAMS(서울대학교, 2007)를 적용하고 이를 검증하기 위한 자료를 확보하고자 하였다.