• 공학교육연구
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• 제7권2호
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• pp.22-39
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• 2004

이 연구는 국가기술자격제도 관리 운영체제에 대한 국가와 민간의 적절한 역할분담 체계가 무엇인지를 알아보고 이를 구축하기 위한 방안을 마련하고자 하는 데 목적이 있다. 이 연구의 목적을 달성하기 위해 국가기술자격제도 관리의 국가와 민간의 역할분담에 대한 방향을 탐색하였다. 또한 국가기술자격제도의 관리 운영 현황을 분석하여 국가중심의 자격제도 운영의 한계를 살펴보았으며, 자격제도 관리 운영에 대한 국가 및 민간의 역할 분담 방안을 제시하였다. 연구방법으로 관련자료의 수집 및 분석, 기업체(사내자격관리자), 업종별 협회(사업주 단체)를 대상으로 한 설문조사, 국가와 민간의 역할 분담 방향을 설정하기 위한 전문가 협의회 개최, 기업체 및 업종별 협회에 대한 의견수렴을 위한 면담조사 등이 실시되었으며, 자격제도 전문가를 중심으로 연구 협력진 구성하여 운영하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.738-743
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• 1991

A multiobjective analysis technique was applied for the optimum operation of pumps and reservoirs in service water transmission systems. Three major objectives were identified and assessed on the normally operating service water transmission systems. They are, 1) stability of pump operation; 2) economic point of view in minimizing the energy cost for pumping; 3) reliability in meeting the stochasticaly varying demands. The measures of these objectives were required times of pump on-offs in stability, required total energy cost in economics, and minimum required storage during the operating horizon in reliability. In order to find the best meeting solution to the decision maker, a set of non-dominated solutions which show the tradeoff relationships between the considering objectives were generated. The DM selects the best solution from this explicit tradeoff relationships using his heuristic decision rules or experience. The theory was verified by applying to the Kumi Service Water System. A combined technique of the ${\varepsilon}-constraint$ and the weighting methods was used to generate the nondominated solutions, and the dynamic programming algorithm was applied to find the optimal solution for the discretized multi-objective analysis problems.

• Archives of Plastic Surgery
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• 제40권2호
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• pp.129-133
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• 2013

Background A pneumatic tourniquet is generally used to achieve a bloodless operation field in hand surgery. However, this has changed with tumescent solution-based wide-awake surgery. This study is a preliminary prospective case series study to elaborate the formula and indications of the tumescent technique in hand surgery without a tourniquet. Methods Seven patients (age range, 4 months to 37 years) underwent hand or upper extremity surgery for conditions such as nerve palsy, electric burn defect, fingertip injury, contracture, constriction ring syndrome, or acrosyndactyly. A "one-per-mil" tumescent solution (epinephrine 1:1,000,000+20 mg lidocaine/50 mL saline) was used to create a bloodless operating field without a tourniquet. Observation was performed to document the amount of solution injected, the operation field clarity, and the postoperative pain. Results The "one per mil" epinephrine solution showed an effective hemostatic effect. The tumescent technique resulted in an almost bloodless operation field in the tendon and in the constriction ring syndrome surgeries, minimal bleeding in the flap and contracture release surgeries, and acceptable bleeding in acrosyndactyly surgery. The amount of solution injected ranged from 5.3 to 60 mL. No patient expressed significant postoperative pain. Flap surgeries showed mixed results. One flap was lost, while the others survived. Conclusions Epinephrine 1:1,000,000 in saline solution is a potential replacement for a tourniquet in hand surgery. Further studies are needed to delineate its safety for flap survival.

• 설비공학논문집
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• 제9권3호
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• 대한전기학회논문지:전력기술부문A
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• 제55권12호
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• pp.514-521
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• 2006

The existing ULTC operation control strategy based on the measured data deteriorates the voltage compensation capability making the efficient corresponding to the load variation difficult by following the fixed load center point voltage. Accordingly, this paper proposes a new on-line fuzzy ULTC controller based on the designed multiple load center points which can improve the voltage compensation capability of ULTC and minimize voltage deviation by moving in real-time the load center point according to the load variation to an adequate position among the multiple load center points designed using the clustering technique. The Max-Min distance technique is adopted as the clustering technique for the decision of multiple load points from measured MTr load current and PTr voltage, and the minimum distance classifier is adopted for the decision of fuzzy output membership function. To verify the effectiveness of the proposed strategy, Visual C++ MFC-based simulation environments is developed. Finally, the superiority the proposed strategy is proved by comparing the fuzzy ULTC operation control results based on multiple load center points with the existing ULTC operation control results based on fixed load center point using the data for three day.

• 비파괴검사학회지
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• 제25권6호
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• pp.439-445
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• 2005

The stud bolt is one of crucial parts for safe operation of reactor vessels in nuclear power plants, Crack initiation and propagation were reported in stud bolts that arc used for closure of reactor vessel and head, Stud bolts are inspected by ultrasonic technique during overhaul periodically for the prevention of stud bolt failure which could induce radioactive leakage from nuclear reactor, In conventional ultrasonic testing for inspection of stud bolts, cracks are detected by using shadow effect It takes too much time to inspect stud bolts by using conventional ultrasonic technique. In addition, there were numerous spurious signals reflected from every oblique surfaces of thread, In this study, the signal processing technique for enhancing conventional ultrasonic technique was introduced for inspecting stud bolts. The signal processing technique provides removing spurious signal reflected from every oblique surfaces of thread and enhances detectability of defects. Detectability for small crack was enhanced by using this signal processing in ultrasonic inspection of stud bolts in Nuclear Power Plants.

• 한국가금학회지
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• 제24권2호
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• pp.91-95
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• 1997

This study was conducted to establish a colostomy technique using cannulation in white Leghorn male chicks. A everted rectum method was used for colostomy from 3 to 20 months old roosters. After 2 or 3 days of operation, blood clots were taken off. At this time, a cannula was also inserted into artificisal annus to keep it open. The cannula was regularly exchanged at every 7 to 10 days. Polyethylene bag and plastic beaker were used for feces and urine collection, respect-ively. The present paper describes the methods of operation, cannulation after colostomy recturn and post-operation management. This method has succeeded in colostomising chickens that survive as long as their normal counterparts.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2310-2318
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• 2018

Critical conduction mode (CRM) operation is more efficient than continuous conduction mode (CCM) operation at low power levels because of the valley switching of switches and elimination of the reverse recovery losses of boost diodes. When using a sensorless digital control method, an error occurs between the actual and the estimated current. Because of the error, it operates as CCM or discontinuous conduction mode (DCM) during CRM operation and also has an adverse effect on THD of input current. In this paper, a current sensorless technique is presented in an inverter system using a bridgeless boosted power factor correction converter, and a compensation method is proposed to reduce CRM calculation error. The validity of the proposed method is verified by simulation and experiment.

• Journal of information and communication convergence engineering
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• 제12권1호
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• pp.53-59
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• 2014

Motion estimation is a core part of most video compression systems since it directly affects the output video quality and the encoding time. The full search (FS) technique gives the highest visual quality but has the problem of a significant computational load. To solve this problem, we present in this paper a modified median (MMED) operation and advanced search strategies for fast motion estimation. The proposed MMED operation includes a temporally co-located motion vector (MV) to select an appropriate initial candidate. Moreover, we introduce a search procedure that reduces the number of thresholds and simplifies the early termination conditions for the determination of a final MV. The experimental results show that the proposed approach achieves substantial speedup compared with the conventional methods including the motion vector field adaptive search technique (MVFAST) and predictive MVFAST (PMVFAST). The proposed algorithm also improves the PSNR values by increasing the correlation between the MVs, compared with the FS method.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.242-245
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• 2009

This paper proposes an algorithm that increases the speed of generating a Fresnel hologram using a recursive addition operation covering the whole coordinate array of a digital hologram. The 3D object designed to calculate the digital hologram used the depth-map image produced by computer graphics (CG). The proposed algorithm is a technique that performs CGH (computer generated hologram) operation with only the recursive addition from the hologram's whole coordinates by analyzing the regularity between the 3D object and the digital hologram coordinates. The experimental results showed that the proposed algorithm increased operation speed by 30% over the technique using the conventional CGH equation.