• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.891-898
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• 2000

Objective : It is difficult to differentiate intramedullary spinal cord tumors preoperatively from non-neoplastic pathologies in patients presenting as non-compressive myelopathies in magnetic resonance imaging(MRI). In this report, the authors reviewed nonneoplastic intramedullary spinal cord lesions preoperatively diagnosed as tumors and discussed their clinical and radiological characteristics and usefulness of surgical intervention. Methods : From January, 1985 to January, 1999, authors experienced eight non-neoplastic pathologies mimicking intramedullary spinal cord tumors and analysed their medical records, radiological findings and histopathological specimens retrospectively. Results : There were five males and three females and the duration of symptoms were from two to 20 months(mean, 9.8 months). The location of lesions were four cervical, one cervicothoracic and three thoracic. All patients manifested sensory abnormality, seven motor weakness, and six bladder symptom. All cases had swollen spinal cords and increased signal intensities in spin-echo sequences. Six cases showed contrast enhancement : four cases were focal and two diffuse. Under the impression of intramedullary tumors, the patients were operated upon. Final diagnoses on the base of clinical and pathologic finding were : three subacute necrotizing myelopathies, two multiple scleroses, two myelopathy of unknown etiology. One case showed no gross abnormality in surgical field in spite of adequate exposure of the lesion, so biopsy was not performed. In that case, postoperative MRI revealed spontaneous resolution of the lesion. Conclusion : MRI is invaluable diagnostic tool in screening myelopathies. However, its high sensitivity and lack of specificity make difficulty in preoperative differential diagnosis of non-compressive myelopathies. Although no surgical morbidity occurred in our series, we sometimes failed to confirm definite diagnosis even with biopsy. In such a circumstance, long-term follow up is needed.

• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.509-513
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• 2000

The physical and electrical characteristics of MgO and Pt thin-films on it deposited by reactive sputtering and rf magnetron sputtering respectively were analyzed with annealing temperature and time by four point probe SEM and XRD. Under annealing conditions of 100$0^{\circ}C$ and 2 hr, MgO thin-film had the properties of improving Pt adhesion to SiO$_2$and insulation without chemical reaction to Pt thin-film and the sheet resistivity and the resistivity of Pt thin-film deposited on it were 0.1288 Ω/ and 12.88 $\mu$$\Omega$.cm respectively. We made Pt resistance pattern on SiO$_2$/Si substrate by life-off method and fabricated Pt thin-film type microheater for thermal microsensors by Pt-wire Pt-paste and SOG(spin-on-glass). In the temperature range of 25~40$0^{\circ}C$ we estimated TCR(temperature coefficient of resistance) and resistance ratio of thin-film type Pt-RTD(resistance thermometer device). We obtained TCR value of 3927 ppm/$^{\circ}C$ close to the bulk Pt value. Resistance values were varied linearly within the range of the measurement temperature. The thermal characteristics of fabricated thin-films type Pt micorheater were analyzed with Pt-RTD integrated on the same substrate. The heating temperature of Pt microheater could be up to 40$0^{\circ}C$ with 1.5 watts of the heating power.

• 한국정보통신학회논문지
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• 제13권6호
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• pp.1091-1098
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• 2009

본 연구에서는 홈 네트워킹 서비스를 위한 인증 시스템을 설계하고 이것을 실제 센서 노드에 적용하였다. 무선 센서 네트워크의 키 관리 기법인 대칭키 사전 분배방식과 계층적인 키 구조를 적용하여 인증키의 노출을 방지하였다. 또한 SPINS를 기반으로 CBC(cipher block chain) 방식의 RC5 암호화 알고리즘을 적용하여 인증키 및 데이터의 암호화를 수행하였다. 베이스 스테이션(BS)과 센서 노드로 실험 환경을 구축하였고, 각 센서 노드들은 수신된 데이터를 암호화된 인증키와 함께 BS로 전송하게 된다. 실험은 홈 네트워크 서비스에서 발생할 수 있는 보안 위협에 대한 시나리오를 설정하여 진행하였다. 이를 위해 TinyOS의 TOS_Msg 데이터 구조를 약간 변경하여 인증을 위한 8바이트의 인증키를 저장하고 각 센서 노드의 인증 및 데이터의 암호화를 가능하게 하였다. 이를 통해 다른 그룹의 센서노드와 BS 사이의 통신 및 악의적인 목적으로 추가된 센서 노드와의 통선으로 인한 오동작을 막을 수 있었고 생체신호와 같은 중요한 데이터를 전송하는 경우 암호화를 통한 안전한 홈 네트워킹 서비스가 가능함을 확인하였다.

• 한국재료학회지
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• 제25권12호
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• pp.647-654
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• 2015

Self-assembled monolayers(SAM) of microspheres such as silica and polystyrene(PS) beads have found widespread application in photonic crystals, sensors, and lithographic masks or templates. From a practical viewpoint, setting up a high-throughput process to form a SAM over large areas in a controllable manner is a key challenging issue. Various methods have been suggested including drop casting, spin coating, Langmuir Blodgett, and convective self-assembly(CSA) techniques. Among these, the CSA method has recently attracted attention due to its potential scalability to an automated high-throughput process. By controlling various parameters, this process can be precisely tuned to achieve well-ordered arrays of microspheres. In this study, using a restricted meniscus CSA method, we systematically investigate the effect of the processing parameters on the formation of large area self-assembled monolayers of PS beads. A way to provide hydrophilicity, a prerequisite for a CSA, to the surface of a hydrophobic photoresist layer, is presented in order to apply the SAM of the PS beads as a mask for photonic nanojet lithography.

• 한국해양학회지:바다
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• 제3권2호
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• pp.53-58
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• 1998

거친 바닥을 포함하고 있는 laminar 에크만층 내 흐름의 방향변화를 파악하기 위하여 바닥경계조건을 Taylor 급수로 전개하여 에크만방정식의 해를 구하였다. 이때 거친 바닥의 거칠기 정도를 나타내는 변수 h/${\delta}_E$(h, 거칠기의 rms 높이; ${\delta}_E$, 에크만층 두께)의 크기를 변화시켜 거칠기에 의한 에크만층 내 흐름의 방향변화(에크만 veering)를 구하였다. 거칠기 증가시 에크만층 내 일정 수심에서 변회각의 크기가 증가할 뿐만 아니라 이에 따른 cross-isobar 수송량은 도리어 감소함으로써, 결과적으로 내부의 지형류 속도가 감소함을 보여주고 있다. 이러한 이론적 결과를 증명하기 위해 회전반 실험을 실시하였고 관측된 결과는 이론적인 것과 잘 일치하고 있다.

• Biomolecules & Therapeutics
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• 제21권4호
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• pp.270-276
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• 2013

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofluorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxide-induced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosis-promoting mediators (i.e., B-cell lymphoma-2-associated ${\times}$ protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.996-1001
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• 2006

Automatic washing machines have been improved and popularized steadily since the first electric washing machine was produced in the early 1900's. Appliance industry has tried to obtain the performance of washing machine with large capacity, high energy efficiency, low vibration and low noise levels. As the installation peace of a washer becomes closer to the living space, vibration and noise problems become more important challenges. In general, a washing machine has four legs to support its body. Four legs of the washing machine should be attached on a floor. If not so, it may cause severe vibration or walking in the spin-drying process. Unfortunately, the floor of an ordinary house is bumpy in general, and the consumers will not accept bolting washing machines to a foundation; moreover, sometimes they move the location of their washing machines to utility rooms or bath rooms or kitchens and don't care for leveling the legs exactly. In this study, we devise an auto-leg system that prevents the occurrence of abnormal vibration and walking of washing machines. It is simply composed of a spring and a friction damper. Some experiments are implemented to show the dynamic characteristics of the three-dimensional auto-legged washing machine model that is located on the even or uneven ground. A spring parameter is optimized to adjust the length of the auto-leg system automatically up to 10 mm irregularity, and the friction damper is designed to decrease a resonance induced by the spring of the auto-leg system. Some numerical results show that placing the proposed auto-leg system in a washing machine makes good performance with low vibration, as well as low noise, regardless of the unevenness of the floor.

• 천문학회보
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• 제41권1호
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• pp.55.2-56
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• 2016

The spin states of asteroids is regarded as an important clue to understand not only the physical property of an individual object but also the dynamical evolution of the of the population as a whole. Single asteroids can be broadly classified into two separate groups according to their rotational states; Principal Axis (PA) and Non-Principal Axis (NPA) rotators. To date, lightcurve observations have been carried out mostly for PA asteroids. However, discovery of NPA objects has recently been increased due to new observing techniques, and this is the reason why rotational properties of NPA rotators became an issue. As a DEEP-South pilot study for NPA, we selected two targets, 5247 Krolv (1982 UP6) and 14764 Kilauea (7072 P-L) considering their Principal Axis Rotation (PAR) code and visibility. Observations were made between Jan. and Feb. 2016 for 17 nights employing Korea Microlensing Telescope Network (KMTNet) 1.6 m telescopes installed at SSO and SAAO using DEEP-South TO (Target of Opportunity) mode. To obtain lightcurves, we conducted time-series photometry using Johnson-Cousins R-filter. Multi-band photometry was also made with BVRI filters at the same time, for taxonomy. Their preliminary lightcurves and approximate mineralogy will be presented.

• 천문학회보
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• 제41권1호
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• pp.54.3-55
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• 2016

DEEP-South Scheduling and Data reduction System (DS SDS) consists of two separate software subsystems: Headquarters (HQ) at Korea Astronomy and Space Science Institute (KASI), and SDS Data Reduction (DR) at Korea Institute of Science and Technology Information (KISTI). HQ runs the DS Scheduling System (DSS), DS database (DB), and Control and Monitoring (C&M) designed to monitor and manage overall SDS actions. DR hosts the Moving Object Detection Program (MODP), Asteroid Spin Analysis Package (ASAP) and Data Reduction Control & Monitor (DRCM). MODP and ASAP conduct data analysis while DRCM checks if they are working properly. The functions of SDS is three-fold: (1) DSS plans schedules for three KMTNet stations, (2) DR performs data analysis, and (3) C&M checks whether DSS and DR function properly. DSS prepares a list of targets, aids users in deciding observation priority, calculates exposure time, schedules nightly runs, and archives data using Database Management System (DBMS). MODP is designed to discover moving objects on CCD images, while ASAP performs photometry and reconstructs their lightcurves. Based on ASAP lightcurve analysis and/or MODP astrometry, DSS schedules follow-up runs to be conducted with a part of, or three KMTNet telescopes.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.626-631
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• 2007

신도시개발 사업은 다양한 공종들이 복합적으로 진행되는 사업으로서 그 규모와 파급효과가 매우 큰 사업이다. 최근 국내 신도시개발 시장은 그 규모가 점차 줄어드는 반면 해외 신도시개발 시장은 투자개발형 사업을 위주로 크게 증가하고 있는 실정이며 이러한 상황 속에서 국내 신도시개발 공기업은 지난 30여 년간 국내에서 쌓은 충분한 경험을 바탕으로 해외 신도시시장에 진출할 필요성이 있다. 이에 본 연구에서는 포커스그룹 인터뷰를 통하여 국내 공기업의 해외 신도시시장 진출과정에서 고려되어야할 핵심요소들을 도출하였으며 중요도성과분석과 내용분석을 통한 설문분석을 바탕으로 신도시개발 공기업의 현황을 파악하고 해외사업진출 가능성을 파악하였다.