Earticle

최근 딥 러닝 알고리듬이 다양한 분야에 적용되어 좋은 성능을 내고 있지만, 소나시스템에는 아직 활발히 적용되지 않고 있다. 본 논문에서는 기뢰와 같은 금속 물체와 바위로부터 반사된 능동소나 수신음 데이터를 딥 러닝 알고리듬의 하나인 컨볼루션 신경망으로 식별하는 실험을 수행하였다. 과적합 방지 및 성능 향상을 위해 데이터 확장을 하였고, 확장 및 하이퍼파라미터 값 변화에 따른 성능 변화를 분석하였다. 훈련데이터를 수신각도에 독립적인 경우와 의존적인 경우로 나누어 실험을 수행하였고, 그 결과 각각 88.9%, 94.9%의 성능을 보였다. 이는 이전 연구에서 인공신경망 및 Support Vector Machine 알고리듬을 적용하여 얻은 성능보다 최대 4.5% 포인트 향상되었다.

Recently, deep learning algorithms have good performance in various fields, but they are not actively applied to sonar systems. In this study, we carried out experiments to classify active sonar returns into a metal object such as a mine and a rock using a convolutional neural network which is one of the deep learning algorithms. Data augmentation is applied on this paper to avoid overfitting and increase performance. And we analyzed performance variation depending on hyperparameter value and change of the number of training data through data augmentation. The experiments are performed with two training data; an aspect-angle independent and an aspect-angle dependent. As a result, the performances are 88.9% and 94.9% in aspect-angle independent and dependent, respectively. These are up to 4.5% point higher than the performance obtained by applying artificial neural network and support vector machine algorithm in the previous study.

본 연구는 열유도 상분리법(thermally induced phase separation, TIPS)을 사용하여, 수처리 분리막에 적용하기 위해, 응고조의 열용량의 변화를 위해 서로 다른 두 용액의 함량을 조절하였다. 또한, 온도의 변화를 통해 분리막의 구조 변화에 대하여 관찰하였다. 분리막을 제조하기 위한 소재로는 수처리 분리막에 주로 이용되는 기계적 물성과 내화학성이 우수한 poly (vinylidene fluoride)(PVDF)를 사용하였고, 첨가제로 실리카를 이용하였다. 희석제는 PVDF와 호환성이 좋은 dioctyl phthalate (DOP), dibutyl phthalate (DBP)를 사용하였다. 응고액의 함량 변화에 따른 열용량 변화에 따라 제조된 분리막의 구조를 관찰하기 위해 SEM 이미지를 촬영하였다. 열용량이 증가할수록 PVDF의 결정화 속도가 느려져 큰 기공을 나타내며 열용량이 작을수록 결정화 속도가 증가하여 작은 기공이 생기는 것을 확인하였다.

In this study, we prepared PVDF membranes via TIPS for water treatment applications. PVDF was used for its excellent chemical and mechanical properties. The effect of coagulation bath composition, temperature, and heat capacity on the overall membrane morphology was studied and observed using SEM. A mixture of DOP and DBP was used as the diluent, and silica was used as an additive. It was observed that as the heat capacity of the coagulation bath increased, the crystallization rate of PVDF decreased yielding larger pores. Also, as the heat capacity of the coagulation bath decreased, the crystallization rate of PVDF increased yielding smaller pores.

많은 제조기반의 중소기업들은 프로세스나 제품을 혁신하기 위해 공공 및 사기업의 지식서비스를 아웃소싱하고 있다. 본 연구의 사례인 K 연구원은 여러 지식서비스를 다양한 조합형태로 제공하는데, 이러한 제공형태의 복잡성으로 인해 지식서비스 사업성과를 정확히 분석한다는 것이 어려운 상황이다. 본 연구는 기존에 성과평가 항목을 상향식으로 선정하는 방식이 아닌 하향식 관점에서 성과항목을 도출하였다. K 연구원 지식서비스 수혜기업인 82개 기업사례에서 74개의 성과항목이 도출되었고, 최종적으로 17개 항목으로 정제하였다. 이후 사례-성과 행렬을 구조화하여 기업별 성과의 유무를 조사하여 이진 데이터로 입력하였다. K-means 클러스터링 분석을 통해 3개의 군집을 각각 '핵심 경쟁력 강화(제품 및 특허)', '국내 및 해외시장 확대', '운영 효율성 제고'로 식별할 수 있었다.

In recent years, many small and medium-sized manufacturing companies are making process innovation and product innovation through the public knowledge services. K Research institute provides different types of knowledge services in combination and due to this complexity, it is difficult to analyze the performance of knowledge service programs precisely. In this study, we derived performance items from bottom-up viewpoints, rather than top-down approaches selecting those items as in previous performance analysis. As a result, 74 items were finded from 82 companies in the K Research Institute case book, and the final result was refined to 17 items. After that a case-performance matrix was constructed, and binary data was entered to analyze. As a result, three clusters were identified through K-means clustering as 'enhancement of core competitiveness (product and patent),' 'expansion of domestic and overseas market,' and 'improvement of operational efficiency.'

본 연구는 열유도 상분리법(thermally induced phase separation, TIPS)을 사용하여, 수처리 분리막에 적용하기 위해, 응고조의 온도 및 열용량의 변화에 따른 분리막의 모폴로지 변화를 관찰하였다. 분리막을 제조하기 위한 소재로는 기계적 물성과 내화학성이 우수한 poly(vinylidene fluoride)(PVDF)와 실리카를 이용하였고, 희석제로는 dioctyl phthalate (DOP), dibutyl phthalate (DBP)를 사용하였다. 다양한 응고액의 열용량 변화에 따른 구조 변화 관찰을 위하여 SEM 이미지를 관찰하였다. 열용량이 증가할수록 PVDF의 결정화 속도가 느려져 큰 기공을 나타내며 열용량이 작을수록 결정화 속도가 증가하여 작은 기공이 생기는 것을 확인하였다.

In this study, we used TIPS (thermally induced phase separation) for the application of water treatment membrane, and observed the change in morphology of separation membrane due to the change of solidification temperature and heat capacity. For manufactured membrane, PVDF and silica with excellent mechanical properties and chemical resistance were used, and DOP (dioctyl phthalate), DBP (dibutyl phthalate) were used as the diluent. Using the SEM (scanning electron microscope), the morphology of each different coagulation solutions of heat capacity change was observed. As the heat capacity increased, the crystallization rate of PVDF was decreased and showed large pore. In contrast, It also confirmed that the smaller heat capacity, the faster the crystallization rate and make smaller pores.

과육색이 다르게 발현되는 사과(Malus domestica L.) 품종의 유전자 발현을 비교하기 위해 2개의 cDNA library를 제작하였다. 붉은 색 과육 품종인 'Redfield'와 백색 과육 품종인 'Granny Smith'의 유전자 발현 차이를 보기 위해 차세대 염기서열 분석(NGS) 기술을 사용하였고 두 품종으로부터 얻은 EST의 염기서열을 결정하고 기존에 보고된 유전자와의 상동성을 분석하였다. HRM 기술은 붉은 색 과육 품종 사과와 백색 과육 품종 사과의 짧은 PCR 증폭산물에서 한 개의 서로 다른 염기서열을 구분하여 분리해낼 수 있다. 'Redfield'와 'Granny Smith'의 EST database로부터 103쌍의 단일염기다형성(SNP) 분자표지를 선발하였고, 붉은 색 과육 품종 10개와 백색 과육 품종 11개를 구분할 수 있는 SNP 분자표지를 HRM 방법으로 분석하였다. 본 연구에서는 사과 EST database를 기반으로 HRM 분석 방법을 이용하여 사과 품종의 적육계와 백육계를 구분할 수 있는 효율적인 SNP 분자표지를 개발하였다. 이러한 SNP 분자표지는 사과육종에 유용하게 사용할 수 있으며 사과 품종의 다양한 색 변화에 관한 분자 기작 연구에 좋은 참고자료가 될 수 있을 것이다.

For comparison of the transcription profiles in apple (Malus domestica L.) cultivars differing in flesh color expression, two cDNA libraries were constructed. Differences in gene expression between red flesh apple cultivar, 'Redfield' and white flesh apple cultivar, 'Granny Smith' were investigated by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the red flesh apple cultivar and white flesh apple cultivar were selected for nucleotide sequence determination and homology searches. High resolution melting (HRM) technique measures temperature induced strand separation of short PCR amplicons, and is able to detect variation as small as one base difference between red flesh apple cultivars and white flesh apple cultivars. We applied high resolution melting (HRM) analysis to discover single nucleotide polymorphisms (SNP) based on the predicted SNP information derived from the apple EST database. All 103 pairs of SNPs were discriminated, and the HRM profiles of amplicons were established. Putative SNPs were screened from the apple EST contigs by HRM analysis displayed specific difference between 10 red flesh apple cultivars and 11 white flesh apple cultivars. In this study, we report an efficient method to develop SNP markers from an EST database with HRM analysis in apple. These SNP markers could be useful for apple marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in apple cultivars.

전신복장법을 이용하여 벼 재배지 농약 살포자의 농약 노출 특성을 구명하고 위해성을 평가하기 위하여 이 연구를 수행하였다. 시험농약은 clothianidin+flubendiamide 6 (2+4)% 액상수화제이었으며, 2,000배 희석액 1,000 L를 각 1 ha 면적의 11개 포장에 power sprayer를 이용하여 11명이 각각 살포한 후 신체 부위별 시료를 채취하여 LC-MS/MS로 잔류농약을 분석하였다. 시험농약의 정량한계는 0.002 ng이었으며, 회수율은 72.9-113.3%이었다. 잔류농약 분석 결과 총 노출량은 $1450.71-4429.38{\mu}g$이었으며, 총 검출량은 11개 포장 모두 살포량 대비 0.03%이었다. 또한 다리(63.49%)에 가장 많은 농약이 노출되었으며, 몸통과 엉덩이(30.30%), 팔(5.66%), 손(0.5%), 호흡(0.03%), 머리(0.01%) 순으로 노출량이 적었다. 노출량을 바탕으로 산출한 clothianidin의 안전한계는 153-466으로 power sprayer를 이용하여 clothianidin를 벼에 살포할 경우 살포자에 대한 위해도는 매우 낮았다.

This study was carried out to evaluate exposure characteristics of clothianidin for paddy field workers during spraying the pesticide onto rice plants and evaluate its potential risk using a whole body dosimetry. Commercial clothianidin+flubendiamide 6(2+4)% SC was diluted 2,000 times and then that was sprayed separately onto eleven rice-growing paddy fields (1 ha per field) at a rate of 1,000 L/ha with power sprayer by eleven workers. Pesticide residues in samples, such as outer/inner clothes, gauze, glass fiber filter and washing solution, were analyzed with an LC-MS/MS after collecting samples. Limit of quantitation of clothianidin was 0.002 ng and mean recoveries found to be 72.4-105.3% in all samples. Total exposure of the pesticide to sprayers were $1450.71-4429.38{\mu}g$ and those were less than 0.03% of total pesticide sprayed in each field. The highest exposure in body parts found in legs (63.49% of the total application). The amount of exposure in trunk and hip, arm, hands, inhalation and head were 30.30, 5.66, 0.50, 0.33 and 0.01% of total application, respectively. Margin of safety of the test pesticide calculated using the amount of the pesticide exposed found to be 153-466, indicating that exposure risk of clothianidin to paddy field sprayer applied by a power sprayer was very low.

이 논문은 연산장치에서 임의의 유효숫자를 제어함으로써 초월함수를 사용하여 유추된 전달행렬법의 세 가지 수치적 불안정성을 분석했고, 이 방법의 전형적인 불안정성은 다음과 같다. 첫째, 연산과정에서 놓친 고유진동수 문제, 둘째, 수치적 불안정성으로 인한 부정확한 결과, 셋째, 고차고유진동수의 계산적 어려움이다. 두 가지 형태의 전달행렬법을 검토했다. 하나의 전달행렬은 곧고 균일한 단면을 가진 보의 굽힘 진동에 대해 기초적인 삼각함수와 하이퍼볼릭 함수로 구성되었다($4{\times}4$ TMM). 다른 하나는 비틀린 보의 연성된 굽힘 진동에 대해 행렬의 각 요소가 지수함수로 구성되었다($8{\times}8$ TMM). 검토된 전달행렬법은 수치적 안정성을 가지고 연산장치의 오버플로($2^{1024}$)까지 220개 이상의 고유치 쌍을 계산 할 수 있다. $4{\times}4$와 $8{\times}8$ 전달행렬법을 사용하여 고유치 쌍을 계산할 수 있는 분명한 범위가 분석된 결과에서 제공되었다.

This study analyzes the cause of three numerical instabilities for the transfer matrix method (TMM) by controlling the precision of the arbitrary digits in the numerical device as follows: (1) the missing natural frequency, (2) the inaccurate results, and (3) the computational difficulty of the high-order natural frequency. Two types of TMMs are examined. One TMM is composed of the trigonometric and hyperbolic functions ($4{\times}4$ TMM) for the transverse vibration of a straight beam, and the other is composed of exponential functions ($8{\times}8$ TMM) for the coupled bending vibrations of a twisted beam. TMMs with numerical stability can obtain the eigenpairs of over 220 up to the overflow ($2^{1024}$) in the numerical device. The explicit range capable of computing the eigenpairs using the $4{\times}4$ and $8{\times}8$ TMMs without any modifications is proposed in the analyzed results.

하천 인근에서 농경지 경작 및 생공용수 등의 이용을 위한 과도한 지하수의 취수는 하천수량 감소의 주요 원인으로 인식되고 있다. 따라서 수자원 관리에 있어서 하천 인근 지하수 관리는 매우 중요하며, 이를 위해서는 하천 인근 지하수 정보 파악이 우선되어야 한다. 본 연구에서는 하천으로부터의 이격거리에 따른 지하수 관정의 비율과 하천 인근에 포함된 관정의 분포 특성을 파악하기 위해 안성천 유역을 대상으로 지하수 취수계획량 현황을 조사하였다. 안성천 수계 전체 관정 중 하천 인근에 포함된 허가관정의 취수계획량 비율은 20.6%, 하천 인근에 포함된 신고관정의 경우는 31.3%로 나타났다. 하지만 하천 인근 관정의 전체 취수계획량 중 허가관정은 11.4%, 신고관정은 88.6%에 해당하는 것으로 나타나 하천인근에서 신고관정의 취수비율이 월등히 높은 것으로 분석되었다. 현재까지는 지하수법에 의해 하천 인근 지하수 개발시 단지 허가관정에 대해서만 의무적으로 지하수영향조사서를 작성하도록 되어있으나 하천 인근의 이용관정 중 신고관정의 양이 훨씬 많은 것을 감안하면 신고관정에 대한 적극적이면서도 신중한 관리가 필요할 것으로 판단된다.

Excessive abstraction of groundwater near streams for agricultural, domestic, or industrial use can significantly reduce the streamflow. Therefore, proper management of water resources must involve careful monitoring of groundwater use near streams. This study investigates the current status of groundwater intake plans in the Anseongcheon watershed, Korea, in order to understand the portion of groundwater wells according to distance from the stream and the distribution of wells near the stream. Among all the wells in the watershed, 20.5% were permitted and 31.3% were declared within 300m from the stream. In particular, among the wells located near streams, 11.4% were permitted and 88.6% were declared among the wells near streams. Therefore, the total amount of groundwater pumping rates from the declared wells is much higher than that from the permitted wells near the stream. Under current guidelines, investigations of the impact of groundwater use near a stream on streamflow depletion should only consider wells permitted by groundwater law. However, prudent management should also pay attention to declared wells, given their large number.

토마토 중 fluquinconazole과 flusilazole의 온실 재배 및 가공과정 중 소실을 구명하기 위하여 온실에서 재배 중인 토마토에 시험농약(fluquinconazole+flusilazole 8.5(7+1.5)% 액상수화제)을 안전사용기준에 준하여 살포한 후 경시적인 잔류량 변화 시험을 위해서는 최종 약제 살포 당일, 1, 3, 5, 7일차에, 가공시험을 위해서는 최종 약제 살포 후 5일차에 시료를 채취하였으며, 가공과정 중 잔류량 변화를 시험하기 위하여 토마토를 퓨레와 주스로 가공하였다. 토마토와 가공품 중 fluquinconazole과 flusilazole의 정량한계는 모두 0.005 mg/kg이었으며, 회수율은 74.8-97.5%이었다. 온실조건에서 토마토 중 fluquinconazole과 flusilazole의 생물학적 반감기는 각각 5.2와 6.4일이었다. 가공에 따른 토마토 및 가공품 중 fluquinconazole과 flusilazole의 평균 잔류수준은 물로 세척 후는 각각 37.34와 79.53%, 끓인 후 여과액에는 각각 8.95와 28.75%, 퓨레에는 3.58과 14.66%, 주스에는 3.34와 13.52%이었다. 이 결과로 미루어 볼 때 토마토 중 fluquinconazole과 flusilazole은 주로 세척과 끓임에 의해 제거되는 것으로 판단되었다.

This study was carried out to investigate residue dissipation of fluquinconazole and flusilazole in field-sprayed tomatoes during greenhouse cultivation and processing. The test pesticide, fluquinconazole+flusilazole 8.5 (7+1.5)% SC, was sprayed onto the tomatoes growing in a greenhouse according to Korea preharvest intervals and then samples were collected on 0 (3 hours after spraying), 1, 3, 5 and 7 days after last application for decline test. For processing test, tomatoes collected at harvest on 5 day after last application were processed to puree and juice. Limits of quantitation of fluquinconazole and flusilazole were 0.005 mg/kg in both tomatoes and their processed products. Recoveries for validation of the analytical methods for fluquinconazole and flusilazole in tomatoes and their processed products ranged from 74.8 to 97.5%. Biological half-lives of fluquinconazole and flusilazole in tomatoes under greenhouse conditions found to be 5.2 and 6.4 days, respectively. Average persistent residue levels of fluquinconazole and flusilazole were 37.34 and 79.53% after washing, 8.95 and 28.75% in filtrates after boiling, 3.58 and 14.66% in puree, and 3.34 and 13.52% in juice, respectively. These results indicated that the test pesticide residues on tomatoes could be largely removed through washing and boiling.

In this paper, we developed a control algorithm to maximize the cleaning performance and the cleaning efficiency of the underwater cleaning robot platform which has been developed for various cistern environment in the industrial field. Through these research and development, we have presented the operation and application of underwater cleaning robots that have been developed, and contributed to commercialization. Finally, this results were verified the effectiveness through actual field experiments.

Purposes : The purpose of this study is to identify factors that have effects on safety activities of hospital personnels by investigating causality between patient safety culture, job stress, safety system and safety activities of faculty and staff member who are working for oriental medicine hospital of university. Methodology : The subjects were 246 employees working in 4 oriental medicine hospitals of university in Daejeon and Chungcheongnam-do. The data were collected from January 16 to January 25, 2017 using a structured questionnaire. For data analysis, descriptive statistics, Pearson correlation coefficient, t-test, ANOVA and Duncan test with SPSS 22.0 were used. Findings : The activity score for patient safety of faculty and staff member, who were experienced at job training program after joining a company and regular training course for qualification or license, was meaningfully higher than that of group who had no job training experience. The result indicated that the higher there is level of safety culture and safety system and the lower there is work stress, the more the activity has positive effect on patient safety. The level score of awareness for safety culture of faculty and staff member in C hospital, which is facing financial crisis in business circumstances recently, showed average value of 3.29. It was significantly lower than that of the other three hospital. Also, The activity score for patient safety was markedly lower than that of the other three hospital. This result become interested in the process of linking non-financial performance and financial performance. The level score of safety activity in A hospital which obtained healthcare accreditation was remarkably higher than that of the other three hospital which didn't certify healthcare accreditation. Pratical Implications : Subjects about Q.I or patient's experience management must be included in curriculum of Oriental medicine. It is necessary to get the effect of job training program for faculty and staff member through the process of preparation for obtaining healthcare accreditation. When the hospital director is appointed, it must be considered that he/she has the ability to attach importance to analysis and management of the factors creating safety accident, and has business mindset for healthcare delivery of customer- centricity. This research showed that financial performance of hospital, which of business environment is favorable; located in metropolitan city and having large scale of hospital and quality of residence rating but low-level of safety culture and safety activity, was lower than that of general hospital situated in small and medium-sized cities. More research needs to be done for answering this result.

Randomly patterned and wet chemical etching processes were used to treat anti-glare of display cover glasses. The surface and optical properties of grain size and surface morphology controlled by randomly patterned etching and wet chemical solution etching were investigated. The surface morphology and roughness of the etched samples were examined using a spectrophotometer and a portable surface roughness (Ra) measuring instrument, respectively. The gloss caused by reflection from the glass surface was measured at $60^{\circ}$ using a gloss meter. The surface of the sample etched by the doctor-blade process was more uniform than that obtained from a screen pattern etching process at gel state etching process of the first step. The surface roughness obtained from the randomly patterned etching process depended greatly on the mesh size, which in turn affected the grain size and pattern formation. The surface morphology and gloss obtained by the etching process in the second step depended primarily on the mesh size of the gel state etching process of the first step. In our experimental range, the gloss increased on decreasing the grain size at a lower mesh size for the first step process and for longer reaction times for the second step process.

Underwater robots operating in constrained underwater environment have requirements for software systems. Firstly, it is necessary to provide reusable common software components for hardware interface of sensors and actuators that are frequently used in underwater robots. Secondly, it is required to support distributed execution environment on multiple embedded controllers. Thirdly, it is need to implement a monitoring system capable of high-speed and large-data transmission for underwater robots operating in an environment where it is difficult to check the robot status. For these requirements, we have designed the layered architecture pattern and applied several design patterns to enhance the reusability and the maintainability of software components, In addition, we overlaid the broker architecture pattern to support distributed execution environments. Finally, we implemented the underwater robot software system using ROS framework based on the software architecture design. In order to evaluate the performance of the implemented software system, we performed an experiment to measure the response time between components and the transmission rate of the monitoring data, and obtained the results satisfying the required performance.

Purpose: The aim of this study was to analyze the factors related to nonunion in tibiotalar arthrodesis. Materials and Methods: Eighty cases of ankle arthritis treated with tibiotalar arthrodesis in our hospital from November 2008 to November 2015 with more than one year follow up were analyzed. Simple anteroposterior and lateral radiographs after 6 and 12 months of surgery were analyzed. Union was defined as more than 50% connection of the trabecular bone at the ankle joint surface in the anteroposterior and lateral radiographs. The nonunion group was defined as no signs of union with persistent pain 9 months after surgery. The surgical approach, type of used screw, preoperative and postoperative ankle alignment, body mass index (BMI), bone mineral density, and patients' prior history were compared between the two groups. Results: There were 69 union cases and 11 nonunion cases. In the patient factors, the gender and BMI was related to nonunion (p<0.05). The mean preoperative and postoperative ankle alignment in the nonunion group was $9.93^{\circ}{\pm}6.92^{\circ}$ and $5.43^{\circ}{\pm}3.35^{\circ}$ respectively, and $9.80^{\circ}{\pm}7.55^{\circ}$ and $5.63^{\circ}{\pm}3.45^{\circ}$ in the union group, respectively; the difference was not statistically significant (p>0.05). In the technical factors, the transfibular approach showed a better relationship but the association was not significant (p<0.05). In 40 cases of the transfibular approach, 12 cases used cancellous screws, and 4 cases showed nonunion due to screw breakage. Conclusion: Technical factors, such as the surgical approach and the type of screw used can be a risk factor in nonunion. In addition, patients' factors, such as gender and BMI, must be considered to reduce the nonunion rate.

기후변화 대응을 위한 청정 화력발전 기술의 일환으로 폐기물과 바이오매스를 중심으로 한 신재생연료의 이용이 크게 증가함에 따라 특히 고온 고압 스팀 생산이 필요한 발전용 보일러 열교환기의 고온부식(High temperature corrosion) 문제가 심각한 현안으로 대두되고 있다. 이러한 문제점은 저급연료에 포함된 염화알칼리 성분이 보일러 내 열교환기 중 표면온도가 가장 높은 과열기(Superheater) 또는 재열기(Reheater)에 점착된 후 염소에 의해 부식이 가속화되어 일어난다. 이를 해결하기 위해 설계 변경, 재료 개선, 연료 전처리 등의 고온부식 회피 방법과 함께 첨가제를 이용한 고온부식 방지 기술이 활용되고 있다. 본 연구에서는 보일러에서 고온부식 방지를 위한 다양한 접근 중 특히 첨가제를 이용한 연구개발 현황을 소개한다.

As the use of waste and biomass increases in a power generation boiler, high temperature corrosion (HTC) problems of boiler heat exchangers are becoming very important. Chlorine of the low-rank fuels is mainly responsible for the HTC issues, which typically occur in the surface of high temperature heat exchanger like a superheater or reheater. In order to mitigate the problem, various approaches have been proposed in terms of design modification, material improvement, fuel pre-treatment and additive utilization. In this study, the current state of research and development focused on the additive method was investigated.

IT project teams are composed of experts from various domains with different backgrounds, such as business and technologies. Thus, enhancing knowledge sharing and increasing team social capital are critical for the success of the project. This study examines the relationship among the team social capital, team climate and team performance. A research model and hypotheses are developed from literature review and empirically validated. The research model consists of team social capital, team climate and team performance. Specifically, team social capital, as antecedents, wasconceptualized asinternal and external differentiated by team boundary, and team climate is conceptualized as innovative climate and supportive climate. Using measures adopted from previous studies, 166 data points were collected to test the research model and related hypotheses. PLS data analysis indicated that internal and external social capitalhave positive effect on innovative climate while internal social capital has a positive effect on supportive team climate. The innovative and supportive climate has significant effect on the team performance. Based on the results, we proposed several team management skills for IT project managers. Theoretical constributions are discussed at the end with limitations and further studies.

본 연구에서는 현재 교량에 사용되고 있는 텐던의 인장력을 측정하기 위한 자기적 비파괴 검사 방법을 연구하였다. 최근 자기적 방법으로 사용되고 있는 초기투자율(${\mu}i$)과 증분투자율(${\mu}{\Delta}$) 측정 방법은 코일을 권선하여 텐던을 자화 시켜야 하고, 텐던의 자기소거상태에서 측정하여야 하는 어려움이 있다. 때문에 본 연구에서는 텐던이 7개의 strand로 꼬여 있는 것을 감안하여, Wiedemann effect를 활용한 방법을 연구하였다. 텐던에 직접 교류 전류를 인가한 후, 인장력을 변화시키면서 그에 따른 텐던의 자화 상태의 변화를 텐던에 부착된 탐지코일(Search Coil on Tendon; SCT)로부터 측정하고 분석하였다. 이를 위하여 본 연구에서는 텐던에 인장력을 2 GPa까지 인가할 수 있는 장치와 텐던에 직접 교류 전류를 인가하여 텐던을 자화시키기 위한 전류공급장치를 제작하였다. 비교실험을 위하여 두 제조회사에서 제작된 동일한 규격의 7-strands 텐던에 대한 인장력에 따른 자화 상태의 변화를 측정한 결과, 텐던에 인가하는 인장력에 따라 텐던에 부착된 탐지코일에서 유도되는 기전력의 변화가 비교적 선형적으로 감소함을 알 수 있었으며, 이는 A회사와 B회사의 텐던에서 모두 유사한 특성을 보여주었다. 따라서 탐지코일을 부착하여 제작한 텐던을 신설되는 교량에 적용한다면, Wiedemann 효과를 활용하여 교량의 안전 진단을 위한 자기적 비파괴 검사 방법으로 적용 가능할 것이라고 생각된다.

In this study, we have constructed a measuring system to investigate tensile stress of tendons, which is employed in bridges, by means of the magnetic non-destructive testing (NDT) method. For the twisted 7-strands tendon, we have used Wiedemann effect. An ac current was applied to the tendon and voltage induced from Search Coil on Tendon (SCT) under applying tensile stress was measured. The measuring system consists of tensile stress applying apparatus up to 2 GPa, and ac current supply to apply current to the tendon directly to magnetize the tendon. We have invested two kinds of tendon which were produced by different companies for testing with constructed measuring system. Voltage induced from SCT was decreased up to 1.5 GPa linearly and two kinds of tendon which were produced by different companies shows similar trends. Thus, Wiedemann effect was also applicable to measure tensile stress of tendon by means of magnetic NDT.

Recently, 3D printing technology has been considered as a core applicable technology because it brings many improvements such as the development of medical technology, medical customization, and reducing production cost and shortening treatment period. This research suggests a market prediction framework for medical 3D printing business. As an immature market situation, it is important to control some uncertainty for market prediction such as a customers' conversion rate. So we adopt decision making tree (DMT) model which used to choose an optimal decision making among diverse pathway. Among medical industries this paper just focuses on dentistry business. For predicting a 5 year period trend expected market size, we identified some replaceable denture procedure by 3D printing, collected related data, controlled uncertain variables. The result shows that medical 3D printing business could be a market of 28.2 billion won at 1st year and in the end of fifth year it could become on a scale of 61.1 billion won market.

본 연구에서는 단일모드 사각형 링 공진기에 테이퍼-스텝 구조를 적용하여 단 방향 발진을 구현하였으며, 다양한 테이퍼-스텝 구조 변수를 갖는 소자를 제작하여 그 특성을 분석하였다. 소자는 InP기판을 기반으로 성장된 InGaAsP/InGaAs 다중 양자 우물구조의 반도체에 제작하였으며, 제작된 소자의 출력과 광 손실을 측정하였다. 이를 바탕으로 주어진 반도체 에피 구조와 단일모드 사각 링 공진기에서의 최적화된 구조 변수를 도출할 수 있었다.

We report on the parameter-dependent optical characteristics of the unidirectional single-mode lasing square ring cavities. Using the taper-step section in the square cavities, the resonant direction can be selected and we characterize the optical losses by changing the taper lengths. Various kinds of square ring cavities are fabricated, based on InGaAsP/InGaAs multiple quantum well semiconductor materials. From the experimental results we obtain the optimized taper length for a given device structure, while maintaining unidirectional single-mode lasing.

바코드 리더를 위한 전자기력을 이용한 소형 회전 무빙 코일 타입 보이스 코일 구동기를 개발하였다. 본 구동기는 1 개의 자석과 1 개의 코일 그리고 1 개의 복원핀으로 이루어진 간단한 구조이다. 구동기는 DC 모터의 선형으로 근사화한 이론적인 모델링으로 해석하고, 유한 요소 해석 프로그램으로 모터 상수와 복원력 상수를 계산하여 동적 성능을 예측하였다. 공진 주파수는 64 Hz 이며 바코드 리더를 위한 50 Hz 의 주파수에서 60 deg 의 반사각을 가짐으로 예측되었다. 시작품을 제작하여 실험을 통하여 3 V 의 입력 전압에서 50 Hz 의 주파수에서 61.8 deg 의 반사각을 가짐을 확인하였다. 제안된 구동기는 Op-amp 를 이용하여 간단한 개루프 제어 회로 구성이 가능하다.

A voice coil actuator with moving coil type for scanning mirror system of barcode reader has been developed. The actuator has a simple structure including a magnet, a coil and a pin. The performance of the actuator is analyzed by a linearized theoretical model. And the dynamic performance of the proposed actuator is predicted through motor constant and restoring constant obtained by finite element simulations. The theoretical model was verified by the prototype which has 64 Hz resonance frequency and 60 deg reflecting angle. We also discovered that that 3 V input can make the actuator rotate over 61.8 deg reflecting angle at 50 Hz resonance frequency. The proposed actuator can simplify its driving configuration because of its implementation of open-loop control.