• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.107-107
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• 2017

최근 과학 기술의 발달과 정보화로 인해 다양한 분야의 방대한 정보들이 디지털화되어 저장되고, 이를 효율적으로 저장하고 관리하는 기술에 대한 수요가 증대하고 있다. 특히, 수자원 분야에서도 지점 관측 형태의 직접 계측방식이 아닌 선, 면 형태의 간접 계측방식의 기술이 개발됨에 따라 짧은 시간 동안 많은 수의 양질의 자료를 취득할 수 있게 되었다. 이에 따라 과거에 비해 방대하고 연속적인 하천공간정보가 축척되었으며, 이를 저장하고 관리하고자 하는 필요성이 대두되고 있다. 하천공간정보 중 하천단면자료는 하천기본계획수립 시 핵심이 되는 자료중 하나일 뿐만 아니라 하천의 흐름 특성을 해석하기 위한 여러 물리 모형의 입력 자료로서, 하천의 물이 흐르는 하도공간을 흐름방향의 횡방향으로 절단하였을 때 생기는 면을 기록한 자료이다. 국가에서는 하천단면자료 계측을 위해 많은 예산을 투입하고 있으며, 실제로 많은 수의 하천에서 하천단면자료를 계측하고 있다. 하지만 계측된 하천단면자료는 컴퓨터를 이용하여 제도하는 응용프로그램용 파일(CAD)로 저장되어, 하천단면자료를 지속적으로 저장 관리 모니터링하기에는 어려운 실정이다. 본 연구에서는 이러한 하천단면자료를 지속적으로 저장 관리 모니터링 할 수 있는 시스템 개발을 목적으로 현재 개발 중인 하천공간정보 표준 자료모형과 하천공간정보를 전송할 수 있는 표준자료 전송 언어인 RiverML을 활용하였다. 본 연구에서 도입한 하천공간정보 표준 자료모형은 하천망을 기반으로 한 상호연계를 기본으로 하고 있어, 하천망을 구성하는 각 하천과 해당 하천의 단면자료 간의 관계를 규명하기 쉬우며, RiverML은 이와 유사하게 하천망을 기반으로 다양한 정보를 전달하기 쉬운 전송언어이다. 또한 국가에서 개발한 공간정보 오픈 플랫폼인 브이월드(Vworld)의 API를 활용하여 저장된 하천단면자료를 표출할 수 있게 하였다. 본 연구의 결과는 하천단면자료 저장 관리 모니터링에 유용하게 사용될 수 있을 뿐만 아니라, 지속적인 개발을 통해 하천에서 계측되는 공간정보뿐만 아니라 하천의 시설물, 생태환경, 문화 등의 하천공간정보과 연계하여 효율적인 시스템을 개발할 수 있을 것으로 사료된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.208-208
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• 2009

최근 광섬유 센서기술의 수요는 전 산업분야에 걸쳐 높아지고 있으며, 이에 비례하여 기업 간, 국가 간 경쟁이 첨예화되고 있다. 또한 소형화, 경량화, 고성능화 센서에 대한 요구도 높아지고 있어 종래의 각종 센서들의 형태와 개선을 위한 연구개발이 매우 활발하게 전개되고 있으므로 이를 대체할 수 있는 광섬유 센서의 수요가 급격히 늘어날 전망이다. 기존 침입자 감지 시스템은 태풍, 낙뢰, 폭설, 폭우 등의 기상변화나 지반 흔들림, 통행차량 진동 및 전자기 간섭 등에 영향을 받아 오작동, 오경보가 빈번히 발생된다. 이러한 문제의 해결책으로 광섬유 센서 케이블을 이용한 시스템이 대안으로 부각되고 있다. 현재 국내에서 군부대, 공항을 중심으로 펜스와 휴전선 철책에 힘입자 감지를 위하여 도입되고 있다. 광섬유 센서 케이블을 사용하는 광망경비시스템은 광섬유 센서 케이블을 그물망 형태(광망)로 만들어 경계 지역에 설치된다. 광망경비시스템의 원리는 광섬유에 광펄스를 입사시켜 순환시키는데 침입자가 광망을 절단하거나 외력을 가할 경우 발생되는 레일리 산란에 기인하는 후방산란과 접속점과 파단점에서 생기는 반사광을 OTDR(Optical Time Domain Reflectometer)로 검출하여 침입상황 및 침입위치를 탐지한다. 그러나 이러한 침입자 감지를 위한 광망경비시스템의 핵심부품인 광섬유 센서 케이블은 기존에 전량 해외수입에 의존하고 있는 실정이며, 지금까지 국내에서 생산하기 위한 제작 기술과 노하우가 초보단계에 머물러 있다. 이러한 광섬유 센서 케이블 제작에 있어서 중요한 부분이 패키징 기술이라 할 수 있다. 이는 광섬유 센서를 일반적인 피복 구조로 패키징하게 되면, 센서 고유의 특성이 패키징 과정과 운반과정, 포설과정에서 변하게 되고 센서로써의 신뢰성이 크게 저하된다. 본 연구에서는 힘입자 감지용 광섬유 센서 케이블의 설계와 제작을 위한 제조공법을 확립하고, 이를 이용해 제작된 광섬유 센서 케이블의 신뢰성 특성을 평가하였다. 설계 제작된 광섬유 센서 케이블의 구조는 멀티모드광섬유(MMF) 에 0.9 mm Tight buffer를 코팅하고, 광심선 주위에 아라미드 얀을 삽입시킨 후 고문자 수지를 적용하여 외부 피복 (jacket)을 하였다. 제작된 광섬유 센서 케이블의 외경 측정결과 기준치 ($2.95\;{\pm}\;0.03$ mm)를 모두 만족하였고, 850 nm 파장에서의 광 손실 측정 결과 4.0 dB/km 이하였다. 또한 주요 항목의 신뢰성 특성 시험결과, 인장강도는 8~10 kg의 인장력을 갖으며 온도순환시험 ($-30^{\circ}C\;{\sim}\;+75^{\circ}C$)에서의 광 손실은 0.6 dB 이하로 나타나 침입자 감지용 광섬유 센서 케이블로 적합함을 확인할 수 있었다.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.218-225
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• 2016

Purpose: The purpose of this study was to evaluate the push-out bond strength of glass-fiber post cemented with different adhesive systems and surface treatments. Materials and methods: 160 tooth samples made from 48 human maxillary single-rooted teeth with similar root length were divided into 4 groups according to the adhesive system (no adhesive, Adper Single Bond 2, Clearfil SE Bond, Clearfil S3). Each group had 4 subgroups according to the post surface treatment methods (no treatment, sandblast, silane, sandblast and silane). Posts (Parapost Fiber White) were cemented with Rely X Unicem. The teeth were sectioned perpendicular to their long axis into 1-mm thick sections. The push-out tests was performed at a speed of 0.5 mm/min. The results were evaluated by 2-way ANOVA, 1-way ANOVA and multiple comparison procedures (Tukey test) (${\alpha}=0.05$). Results: Tukey test showed that the adhesive system significantly influenced the push-out strength. The Clearfil SE Bond group showed the highest value. Post surface treatments showed no significant effect. Conclusion: Bond strength of glass-fiber post cemented with self-adhesive resin cement using Clearfil SE Bond showed significantly higher values compared to other adhesive systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.195-204
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• 2020

To help solve the problems of how to set the optimal sawing force and the optimal controller parameters for different sawing conditions, a mathematical model of a proposed sawing system was established according to the principle of sawing force control. The conventional PID control method was then used for further research of the closed-loop control of the sawing force. Finally, through simulation and experimental research, the influence rule of the controller parameters and sawing load on the control performance and the relationships between the sawing width and controller parameters (proportion coefficient) and the sawing force setting value were obtained, from which a system scheme for intelligent sawing control of a band sawing machine was proposed. The research shows that the sawing efficiency of the intelligent sawing system was 18.1 (48%) higher than that of the original sawing system when sawing a grooved section sawing material, which verifies the good control effect of the proposed scheme.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.969-977
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• 2001

The purpose of this study was to investigate disinfection state and effective factors of utensils and equipments used to foodservice of elementary schools in Busan area, The questionnaire which was administered to 160 dietitians was used in this study as a survey method. The results were as follows. The disinfection method of tray was mainly used by electric gas. Table and other products of stainless steel sanitized by sodium hypochlorite and hot water, but above 51% of slicer. grinder and peeler were not sanitized after used. The products of wood and plastic also used mainly sodium hypochlorite and hot water as sanitizers. In disinfection time, knife, wood spoon and plastic products should be sanitized on demand, but 30.9~53.5% of this utensils except rice scoop were sanitized on demand that showed deficiency of cognition for sanitation. The disinfection of most of utensils and equipments was conducted every day, but food case, slicer, peeler, grinder and wood spoon showed lower disinfection frequency than other products, The method of disinfection was related to dietitians age and career number of total serving, duration of foodservice and serving place, The disinfection time was also affected by dietitians age and educational level, and serving place. The disinfection frequency was affected by number of employee, number of total serving and duration of foodservice. Therefore based on the results of this study, it should be given to the microbiological study on disinfection method of utensils such as slicer, grinder, peeler, large spoon, plastic prouducts and the dietitians sanitation training also should be conducted continuously.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.5
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• pp.430-436
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• 2014

The mission objective of STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project) classified as a pico-class satellite is to verify the technical effectiveness of payloads such as variable emittance radiator, SMA washer, oscillating heat pipe and MEMS based solid propellant thruster researched at domestic universities. In addition, the MEMS concentrating photovoltaic power system and the non-explosive holding and separation mechanism with the advantages of high constraint force and low shock level will be developed as the primary payloads for on-orbit verification. In this study, the feasibility of the mission actualization has been confirmed by the preliminary system design.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.33-38
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• 2010

A microfluidic system has been developed using biomaterial for the measurement of cupric ion concentration. The cell-membrane-mimicking bilayer lipid membrane(BLM)-coated silver electrode was used for the sensing of cupric ion concentration. The silver-supported BLM could increase its stability. A silver-supported bilayer lipid membrane(s-BLM) was easily obtained using its self-assembling characteristics by immersing silver wire into lipid(phosphatidylcholine; PC) solution and then dipping into aqueous KCl solution. These s-BLMs were used to determine the relationship between $Cu^{2+}$ concentration and current crossing s-BLM. Their relationship showed high linearity and reproducibility. The calibration curve was constructed to express the relationship between $Cu^{2+}$ concentration and current in the $Cu^{2+}$ concentration range of 10 and $130{\mu}M$. This calibration curve was used to measure $Cu^{2+}$ concentration in an unknown sample. Microfluidic system with s-BLM was made of PDMS(polydimethyl siloxane) using typical soft photolithography and molding technique. This integrated system has various functions such as activation of the silver surface without cutting silver wire, coating of BLM on silver surface, injection of KCl buffer solution, injection of $Cu^{2+}$ sample and measurement of $Cu^{2+}$ concentration in the sample.

• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.326-333
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• 2005

Phase-only encryption scheme using exclusive-OR rules in Fourier plane and a single path decryption system are presented. A zero-padded original image, multiplied by a random phase image, is Fourier transformed and its real-valued data is encrypted with key data by using XOR rules. A decryption is simply performed based on 2-1 setup with spatial filter by Fourier transform for multiplying phase-only encrypted data by phase-only key data, which are obtained by phase-encoding process, and spatial filtering for zero-order elimination in inverse-Fourier plane. Since the encryption process is peformed in Fourier plane, proposed encryption scheme is more tolerant to loss of key information by scratching or cutting than previous XOR encryption method in space domain. Compare with previous phase-visualization systems, due to the simple architecture without a reference wave, our system is basically robust to mechanical vibrations and fluctuations. Numerical simulations have confirmed the proposed technique as high-level encryption and simple decryption architecture.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.271-276
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• 2008

Ribosome stalling by nascent sticky peptide has been reported in several organisms across the kingdom. To test whether small subunit (SSU) rRNA is involved in this phenomenon, we developed a genetic system that utilized the specialized ribosome system to isolate SSU rRNA mutants that enable ribosomes to bypass the SecM-derived sticky peptide in protein synthesis. In this system, CAT-SecM mRNA, which encodes CAT protein containing the sticky peptide derived from SecM, is only translated by specialized ribosomes. These ribosomes were shown to transiently stall on CAT-SecM mRNA followed by the synthesis of the sticky peptide. Expression of specialized ribosomes resulted in the decreased steady-state level of CAT-SecM mRNA, which is consistent with a notion that ribosome stalling induces mRNA degradation. Isolation and characterization of SSU rRNA mutations using this genetic system that are sufficient to circumvent ribosome stalling induced by the SecM-derived sticky peptide will provide evidence of SSU rRNA function in mRNA cleavage.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.636-644
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• 2004

Recently, self-etching adhesive system have been developed and bonding procedures simplified into one or two steps, which are simultaneously applied to both enamel and dentin. These systems are easy to use and have the potential for good clinical success. The purpose of this study is to evaluate in vitro the microleakage on the cementum/dentin and enamel walls in composite resin restoration of Class V cavities, regarding the use of different adhesive systems. 30 human premolars were divided into 3 groups. A standardized Class V preparation was prepared on the buccal and lingual surface of each premolar. The preparation were made parallel to the cementoenamel junctions, with the gingival half of the preparation extending 1mm apical to the cementoenamel junction. After adhesive system was applied to teeth as manufacture's recommendation, hybrid resin composite was filled in bulk into the preparation and light polymerized according to manufacturer's recommendations. Specimen were stored in distilled water at $37^{\circ}C$ for 5 days and thermocycled 1000 times ($5^{\circ}C{\pm}2^{\circ}C\;and\;55^{\circ}C{\pm}2^{\circ}C)$, then immersed in a 2% methylene blue solution for 12 hours. After sectioning mesio distally through the restorations, the degree of dye penetration was scored under a stereomicroscope at ${\times}\;25$ magnification. The data were analyzed statistically using t-test and one-way ANOVA. The results were as follows: ${\cdot}$ There is no adhesive system which can prevent microleakage perfectly. ${\cdot}$ There is significant difference in microleakage between enamel margin and dentin margin (p<0.0001). ${\cdot}$ In enamel margin, self-etching primer systems did not show any significant difference comparing total-etching system. In denin margin, self-etching primer systems did not show any significant difference comparing one-bottle adhesive system used in combination with total-etching.