수리조선 작업장에서의 공기중 석면 노출에 관한 연구

심상효,정희태,송기민,김윤신,강용선,Sim, Sang-Hyo,Chung, Hee-Tae,Song, Ki-Min,Kim, Yoon-Shin,Kang, Yong-Seon 한국환경보건학회 2008 한국환경보건학회지 Vol.34 No.4

This paper aims to provide basic data for work environment control, prevention of worker exposure to asbestos and improvement of air quality to protect workers ‘health after measuring the level of airborne asbestos and workers' exposure in a shipbuilding repair businesses. For this study, a total of 27 samples were collected from 27 workers who had been exposed to asbestos during engine, piping, boiler and other manufacturing processes in 'A' Shipbuilding Repair Company in Gyeongnam. This research was conducted from Oct. 1 to 30, 2007 and had the following results: The target group (27 workers) consisted of all men with an average age of 35.9 years and 6.6 years of work on average. Among them, fifteen 15 (55.6%) were smokers. In terms of their duties at work, there were 12 plumbing repair engineers (44.4%), 8 boiler repair engineers (29.6%) and 7 engine engineers (25.9%). The geometric mean concentration of airborne asbestos was 0.004 f/cc. A total of 4 samples exceeded the exposure limit. In particular, three exceeded the legal limit by more than double, which means that some workers have been highly exposed to asbestos. In terms of the concentration of asbestos fibres by work process, plumbing repair was the highest (0.0071 f/cc($0.001{\sim}0.57\;f/cc$)) while boiler was the lowest (0.0015 f/cc($0.001{\sim}0.007\;f/cc$)). Based on this study, proper action needs to be taken as soon as possible to protect workers from the threat of asbestos.

UHF대역 RFID 수신단(리더)의 지터(비트동기) 및 글리치 제거회로 설계

김상훈,이용주,심재희,이용석,Kim, Sang-Hoon,Lee, Yong-Joo,Sim, Jae-Hee,Lee, Yong-Surk 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.1A

본 논문에서는 ISO/IEC 18000-6C 표준안을 만족하는 UHF대역 RFID 수신단(리더)의 지터(Jitter)처리와 글리치제거 알고리듬 및 설계방안을 제안하고 이를 이용한 리더를 구현하여 실제 TI(Texas instrument) Gen2 태그의 응답을 분석하였다. ISO/IEC 18000-6C표준안은 Reader에서 Tag로 데이터 전송 시 +/-1%의 오차와 Tag에서 Reader로 데이터 전송 시 최대 +/-22%의 오차를 허용하도록 정의하고 있다. 이러한 허용오차범위 내의 데이터에 대해 본 논문에서 제시한 회로는 기존의 PLL(DPLL, ADPLL)을 이용한 방식이 아닌 최대허용치(tolerance)와 허용치누적을 이용하여 일정치의 오차범위를 허용하며 디코딩 하도록 설계하였다. 또한 글리치와 지터제거 알고리듬의 기본원리를 동일하게 구성하여 글리치제거와 지터제거를 따로 구분하지 않고 하나의 기능으로 동작하게 한다. 주 클럭은 19.2MHz로 설정하였으며 LF는 국내 전파법에 맞도록 40kHz로 설정하였다 시뮬레이션결과 15%이하의 위상지터를 가진 입력데이터에 대해 판독에러율은 0이었으며 $15%{\sim}22%$ 위상지터를 가진 입력데이터에 대해서 는 0.000589였다. 그러나 동적LF생성회로를 사용한 결과 $15%{\sim}22%$ 위상변화를 가진 입력데이터에 대해 판독에러율은 0이었으며 표준안에 정의된 최대 +/-22%오차 범위내의 지터 발생에 대해서 판독에러율은 0이었다. In this paper, we propose an implementation and an algorithm of 'Jitter and Glitch Removing Circuit' for UHF RFID reader system based on ISO/IEC 18000-6C standard. We analyze the response of TI(Texas Instrument) Gen2 tag with a reader using the proposed algorithm. In ISO/IEC 18000-6C standard, a bit rate accuracy(tolerance) is up to +/-22% during tag-to-interrogator communication and +/-1% during interrogator-to-tag communication. In order to solve tolerance problems, we implement the Jitter and Glitch Removing Circuit using the concept of tolerance and tolerance-accumulation instead of PLL(DPLL, ADPLL). The main clock is 19.2MHz and the LF(Link Frequency) is determined as 40kHz to meet the local radio regulation in korea. As a result of simulations, the error-rate is zero within 15% tolerance of tag responses. And in the case of using the adaptive LF generation circuit, the error-rate varies from 0.000589 to zero between 15% and 22% tolerance of tag responses. In conclusion, the error-rate is zero between 0%-22% tolerance of tag response specified in ISO/IEC 18000-6C standard.

n-GaAs 구조에서의 ArF excimer laser annealing에 따른 Photoreflectance 특성 연구

김기홍,유재인,심준형,배인호,임진환,김진희,유재용,Kim, Ki-Hong,Yu, Jae-In,Sim, Jun-Hyoung,Bae, In-Ho,Lim, Jin-Hwan,Kim, Jin-Hi,Yu, Jae-Yong 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.2

n-GaAs의 시료를 furnace annealing 처리와 laser annealing 처리를 한 후, PR 방법으로 비교 조사하였다. 시료는 Furnace annealing을 5 분간 $400{\sim}800^{\circ}C$에서 처리한 시료와 ArF excimer laser($30{\sim}50\;W$)로 5 분간 Laser annealing 처리 한 시료로 준비하였다. Furnace로 annealing을 한 경우에 주 신호(정점)는 1.43 eV에서 관측되었는데 비해 laser로 annealing 한 샘플은 1.42 eV로 0.01 eV가 더 작게 관측되었다. 이는 laser annealing이 furnace annealing 보다 표면과 내면에서 일어나는 열처리 효과가 더 고르게 일어나가 때문이다. We investigated variation of the photoreflectance(PR) signals for n-GaAs furnace and laser annealed. The samples were annealed by using ArF excimer laser(5 min, $30{\sim}50\;W$) and furnace(5 min $400{\sim}700^{\circ}C$). The PR signals(top point) measured from the ArF excimer laser annealed sample showed 1.42 eV and furnace annealed sample showed 1.43 eV. This result is ArF excimer laser annealed sample was uniform annealed surface and inter state.

CMOS RFIC 설계를 위한 MOSFET 모델링과 파라미터 추출 방법

심용석,한기원,양진모 대구대학교 정보통신연구소 2003 情報通信硏究 Vol.2 No.1

고주파수 영역에서 동작하는 초미세 MOSFET를 위한 새로운 소신호 모델과 파라미터 추출방법을 제안되었다. 이 모델은 BSIM3v3 코어에 기판회로망 모델과 기생소자들이 추가된 매크로 모델로 구현되었다 모델 파라미터들은 공통-소오스로 구성된 다양한 크기의 nMOS 트랜지스터의 측정된 S-파라미터로부터 직접 추출된다. 직접 추출은 활성영역에서 동작하는 등가회로에서 Z와 Y 파라미터를 이용하였다. 0.5 ㎓에서 20 ㎓ 범위까지 측정된 S-파라미터와 소신호 모델의 시뮬레이션 결과는 우수하게 일치하였다. A new small-signal model for deep submicrometre MOSFET for high frequency operation and its parameter extraction method are proposed. The model is implemented as macromodel with substrate network model and parasitic elements added to the BSIM3v3 core. Model parameters are directly extracted from S-parameter data measured from common-source structured and various sized nMOS transistors. Direct extraction is performed by Z and Y parameter analysis on the equivalent circuit in the saturation region of operation. Excellent agreement between the simulation results of the small-signal model and measured S-parameters at vinous-sized MOS transistor in the range from 0.5 GHz to 20 GHz has been obtained.

무인계산 게이트용 UHF대역의 RFID 라벨태그 안테나에 관한 연구

이재용,심용석,양진모 대구대학교 정보통신연구소 2010 情報通信硏究 Vol.7 No.1

In this paper, we presented a specific UHF RFID label-type tag antenna for unattended payment gateway system to avoid null point by improving radiation patterns and directivity. The proposed antenna was constructed with form of microstrip line on a thin PET substrate for low-cost fabrication. We built some sample antennas and measured the antenna characteristics such as return loss, radiation patterns, and read range. The operating frequency of the tag antenna is 0.7-1.06GHz under -3dB(VSWR<2) return loss. The average readable range of the tag with a conventional RFID reader is 3.75m and the maximum readable range at an echoic chamber is about 5.68 to 6 m. 본 논문에서는 방사 패턴과 방향성을 향상시켜 널 구역을 제거한 무인 계산 게이트 시스템용 UHF RFID 라벨형 태그 안테나를 제안하였다. 제안된 안테나는 PET 기판에 쉽게 인쇄할 수 있어 제조 단가 절감을 통해 대량 생산이 용이하다. 최적화된 RFID 태그 안테나의 표본 안테나를 제작하고 반사손실, 방사패턴, 인식거리 등을 측정하였다. 태그 안테나의 동작 주파수는 반사손실 -3dB(VSWR<2) 기준으로 0.7-1.06 GHz이며, 고정용 리더시스템을 이용한 태그의 평균 인식거리는 3.75m, 무반사실에서의 최대 인식거리는 5.68-6m였다.

RF용 MOSFET를 위한 BSIM3v3 모델의 I-V 파라메터 최적화

심용석,강학진,양진모 대구대학교 정보통신연구소 2003 情報通信硏究 Vol.1 No.2

본 논문에서는 고주파 영역에서 정확한 동작을 예측하는 MOSFET 모델에서 핵심 역할을 하고 있는 BSIM3v3 모델의 정확한 대신호 전류-전압 특성을 위한 직류 모델 파라미터의 최적화 방법을 제안하였다. BSIM3v3의 직류 모델 파라미터는 변화가 허용되는 범위 내에서 측정된 직류 전류-전압 곡선과의 일치로 추출하였다. 또한 MOSFET의 다양한 크기에서 파라미터의 최적화를 수행하여 그 평균값을 취함으로써, 트랜지스터의 크기에 무관한 파라미터를 추출하였다. This paper proposes a DC parameter optimization method that finds the most appropriate DC paramtcr set of BSIM3v3 model accurately represent DC I-V characteristics of MOSFET devices in the giga frequency ranges. The DC I-V characteristics of BSIM3v3 model was varied by changing the DC parameter set (XL, XW, TOX, RSH, DELVTO) in order to fit the measured DC characteristics of various sized RF MOSFETs. The value of the DC parameter set was obtained by averaging the result of optimized values for various sized MOSFETs.

순천향대학교 사회과학대 학생의 진로인식 및 진로지도개선에 관한 연구

심영수,차석빈,김용하,최한준 순천향대학교사회과학연구소 2003 순천향 사회과학연구 Vol.9 No.1

This study conducted an empirical research to find ways to guide the career of college students in the social science at Soonchunhyang university. Research findings are as follows. 1) About 42% respondents answered that they did job-seeking efforts. 2) With regard to job preparing efforts, students spent their time on improving their English ability, major classes, computer ability, and license obtaining. 3) Job-related information sources in the school were not fully utilized by the students. 4) In the future, students hope that our school strengthen its PR efforts, open more English-related classes, improve its school image as a local university, and provide more job-related information The study concludes with implications of the study results and suggestions for career guidance of students.

AHP 기법을 이용한 멀티미디어 저작도구 평가 및 선정에 관한 연구

심상천,김용겸 한국경영과학회 2004 經營 科學 Vol.21 No.2

This study addresses the evaluation criteria of multimedia authoring tools (MAT_s), the way which decision-maker can exclude outlier matrix from group using the concept of the compatibility index, and how AHP can be applied to the selection of MAT_s in a group decision-making environment. The AHP technique allows an evaluator to quantity the relative importance of elements at each hierarchy and to calculate the composite relative weights for each product (i.e. MAT_s). This decision process allows setting to priority of the MAT_s based on the AHP. The results indicated that technical ability of MAT_s was the most significant factor in affecting their decision, trailed by managerial efficiency and vendor support. To the experts, multimedia data support was the less important than development interface. Also, the results indicated that product A(0.510) was their first choice, trailed by product C(0.286) and B(0.204). Assessing the composite relative weights revealed that expert group's members were consistent with the rankings of decision variables(evaluation criteria variables) statistically in selecting their MAT_s. Therefore. we believed that expert group's members have achieved sufficient agreement to permit the use of geometric mean to average the group's preference without obscuring the differences of individual opinions

RF-MOSFET의 개선된 BSIM3 소신호 모델과 측정기반 파라미터 추출

심용석,김정보,양진모 대구대학교 정보통신연구소 2004 情報通信硏究 Vol.3 No.1

RF 영역에서 동작하는 초미세 MOSFET를 위한 새로운 소신호 모델과 파라미터 추출방법을 제안하였다. 이 모델은 BSIM3v3 코어에 기판 회로망 모델과 기생소자들이 추가된 매크로 모델로 구현되었다. 모델 파라미터들은 공통-소오스로 구성된 다양한 크기와 바이어스 조건하에서 nMOS 트랜지스터의 측정된 S-파라미터로부터 직접 추출되었다. 직접 파라미터 추출은 활성영역에서 동작하는 등가회로에서 Z와 Y 파라미터를 이용하여 임베이딩 기법으로 이루어 졌다. 0.5 GHz에서 20 GHz 범위까지 측정된 S-파라미터와 소신호 모델의 시뮬레이션 결과는 우수하게 일치하였다. A new small-signal model for deep submicrometre MOSFET for radio frequency operation and its parameter extraction method are proposed. The model is implemented as macromodel with substrate network model and parasitic elements added to the BSIM3v3 core. Model parameters are directly extracted from S-parameter data measured from common-source structured and various sized and biased MOS transistors . Direct parameter extraction is performed by embedding technique using Z and Y parameter analysis on the equivalent circuit in the saturation region of operation. Excellent agreement between the simulation results of the small-signal model and measured S-parameters at virious-sized MOS transistor in the range from 0.5 GHz to 20 GHz has been obtained.

정전기적으로 분산된 콜로이드 실리카 입자의 코팅

沈秀萬,崔鎔成 홍익대학교 산업기술연구소 1996 産業技術 Vol.6 No.-

Spherical colloidal particles of silica in 0.1㎛ diameter were synthesized dispersed in water electrostatically by adjusting pH. The particles in suspensions were deposited using dip-coating on a soda-lime glass substrate. Total potential energy between the particles and the substrate was calculated and the result was discussed with the adhesion and arrangement of the deposited particles. Particles deposited from a suspension of pH=4 were removed after washing with deionlzed water due to the flocculation of the particles arising from an attraction force between the particles. Deposition of a suspension of pH=8 resulted in a dense coating that the particles were uniformly adhered. Whereas, the deposition with a suspension of pH=6 resulted in a realtively porous coating that the particles were less uniformly adhered. The dense and uniform packing of the particles was attributed to a repulsion force existing between the particles.