• 경영과정보연구
• /
• 제4권
• /
• pp.557-572
• /
• 2000

Nowadays, after beginning of 21 centuries, owing to simplify market, the world is in the era of an influx of new paradigm that requires infinite competition. The manufacturing industries of Korea are in need of casting off high cost and low efficiency structure. The forfeiture of competition is resulted from the lost of level in quality of product. Today, the achievement of competitive product quality is coming from the following factors, that is., quality control, quality of service, marketing, human resources, finance, etc., together with process management. While Six Sigma, a newly introduced method to achieve process qualify outcome by sector of enterprise, is now being enjoyed a high reputation as a key device for competition by superiority enterprises in the United States, it has not been introduced sufficiently in the domestic enterprises yet. In our research, we, first of all, organized systematically the materials being released up to now. Furthermore, we looked over case studies of the American enterprises that apply Six Sigma strategy very successfully. Finally, we discussed the situation of domestic enterprises which are about to importing Six Sigma strategy as well as main causation of success by adopting it. While the enterprises approach Six Sigma strategy not in the way of on time and short term but in the way of long term, consistent renovation and persistent innovation we can assure that they will produce the highest quality and globally competitive products which are second to none.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제10권1호
• /
• pp.37-47
• /
• 2018

Dynamic simulation is critical for electrical ship studies as it obtains the necessary information to capture and characterize system performance over the range of system operations and dynamic events such as disturbances or contingencies. However, modeling and simulation of the interactive electrical and mechanical dynamics involves setting up and solving system equations in time-domain that is typically time consuming and computationally expensive. Accurate assessment of system dynamic behaviors of interest without excessive computational overhead has become a serious concern and challenge for practical application of electrical ship design, analysis, optimization and control. This paper aims to develop a systematic approach to classify the sophisticated dynamic phenomenon encountered in electrical ship modeling and simulation practices based on the design intention and the time scale of interest. Then a novel, comprehensive, coherent, and end-to-end mathematical modeling and simulation approach has been developed for the latest Medium Voltage Direct Current (MVDC) Shipboard Power System (SPS) with the objective to effectively and efficiently capture the system behavior for ship-wide system-level studies. The accuracy and computation efficiency of the proposed approach has been evaluated and validated within the time frame of interest in the cast studies. The significance and the potential application of the proposed modeling and simulation approach are also discussed.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 추계학술대회
• /
• pp.1018-1021
• /
• 2009

무선 센서 네트워크는 특정지역에서 데이터를 수집하여 처리는 작은 센서 노드들로 구성된다. 이러한 센서들은 최초로 설치된 이후에는 배터리로 동작되며, 동작기간이 수개월에서 수년까지 지속되어야 함으로 제한된 자원을 효율적으로 활용할 수 있어야 한다. 본 논문에서는 데이터 중심개념을 적용한 Directed Diffusion의 기본동작구조에 RHC(rounting history cache)를 적용하여, 데이터 전송경로 설정에 신뢰성과 효율성을 높인다. 제안하는 RHC 알고리즘은 각 센서노드가 자신의 RHC를 주기적으로 업데이트하여 최적화경로를 저장하고 있기 때문에, 이벤트 발생시마다 경로를 재설정하여 에너지가 낭비되는 것을 최소화 하였고, 중복메시지의 최소화로 신뢰성을 향상시켰다.

• Advances in aircraft and spacecraft science
• /
• 제9권4호
• /
• pp.335-347
• /
• 2022

Airport operations are well-known as a bottleneck in the air traffic system, putting growing pressure on the world's busiest airports to schedule arrivals and departures as efficiently as possible. Effective planning and control are essential for increasing airport efficiency and reducing aircraft delays. Many algorithms for controlling the arrival/departure queuing area are handled, considering it as first in first out queues, where any available aircraft can take off regardless of its relative sequence with other aircraft. In the suggested system, this problem was compared to the problem of scheduling n tasks (plane takeoffs and landings) on a multiple machine (runways). The proposed technique decreases delays (via efficient runway allocation or allowing aircraft to be expedited to reach a scheduled time) to enhance runway capacity and decrease delays. The aircraft scheduling problem entails arranging aircraft on available runways and scheduling their landings and departures while considering any operational constraints. The topic of this work is the scheduling of aircraft landings and takeoffs on multiple runways. Each aircraft's takeoff and landing schedules have time windows, as well as minimum separation intervals between landings and takeoffs. We present and evaluate a variety of comprehensive concepts and solutions for scheduling aircraft arrival and departure times, intending to reduce delays relative to scheduled times. When compared to First Come First Serve scheduling algorithm, the suggested strategy is usually successful in reducing the average waiting time and average tardiness while optimizing runway use.

• Mass Spectrometry Letters
• /
• 제15권1호
• /
• pp.49-53
• /
• 2024

Ceramide is a lipid in which sphingoid bases and fatty acids are linked by amide bonds. As a marker of skin disease in the human stratum corneum, its disease-causing and therapeutic effects have been partially confirmed, and it is therefore an important element in commercially available cosmetic formulations. However, structural diversity caused by differences in the chain length, number, and location of hydroxyl groups makes quality control difficult. In this study, a method was established to separate different ceramide species using reversed-phase LC-MS/MS and thus enable qualitative evaluation. Separation of four standards was achieved within a short retention time, and the accuracy and sensitivity of the method were demonstrated by the low limit of detection (LOD) calculated based on the calibration curve showing linearity, with R² > 0.994. After verification of reproducibility and reliability through intra- and inter-day analyses, the efficiency of the method was confirmed through analysis of commercial cosmetic raw materials.

• 한국산학기술학회논문지
• /
• 제17권8호
• /
• pp.722-727
• /
• 2016

본 연구에서는 전류효율 향상을 통하여 전해연마 공정 중 발생하는 폐산 폐기물 발생량을 감소시키고자 하였다. 구형 부스바와 Taguchi 기법을 이용하여 전해연마 공정의 최적 조건을 도출하였다. 전해연마 공정 중 전류효율에 영향을 미치는 제어인자로 전류밀도, 전해연마 시간, 전해액 온도, 유량을 선택하였다. 각 제어인자에 대하여 3수준을 고려하여 직교 배열표를 작성하여 실험을 수행하였다. Taguchi 기법에 따라 망대특성 SN비를 산출한 결과 전류밀도가 가장 큰 영향을 미치고 전해연마 시간이 가장 적은 영향을 미치는 것을 확인하였다. 폐산 폐기물 발생량을 최소화할 수 있는 최적 조건은 전류밀도 $45A/dm^2$,전해연마 시간 4 min, 전해액 온도 $65^{\circ}C$, 유량 7 L/min였다. 분산분석 결과 전류밀도, 전해액 온도, 유량이 신뢰수준 95%에서 유의함을 확인하였다. 구형 부스바 사용으로 접촉 면적 및 접촉력 증가로 전류효율이 향상되어 폐산 폐기물 발생량을 감소시킬 수 있었다. 부스바의 형태(선 접점 부스바, 반구형 면 접점 부스바, 구형 면 접점 부스바)에 따른 전류효율의 영향과 관련한 비교 연구가 향후 진행될 예정이다.

• 한국발생생물학회지:발생과생식
• /
• 제14권4호
• /
• pp.261-268
• /
• 2010

As in the O. mykiss electrophoretic profiles of RNA, the signals of each RNA sample from 9 individual tissues such as liver, muscle, brain, heart, pituitary gland, kidney, intestine, spleen and gill similar to positive control were obtained. The tissue distributions of the complimentary DNA (cDNA) of O. mykiss four genes were analyzed using quantitative real-time PCR with primer sets for tissue expression analysis. In this rainbow trout species, author obtained bands of various sizes, ranged from 700 bp to 1,400 bp. A dissociation curve was made at the end of each run to make sure that there was no non-specific amplification. Supplementarily, the Ct of each DNA was compared. The Ct values of vinculin with rainbow trout tissues were determined in a manner similar to those for agouti-related protein (AgRP) and melanocortin receptors (MC4R I and MC4R II). Further, obtained Cts for standard curve of each DNA were affected by specific product (vinculin, AgRP and MC4R II genes). After several experiments with four individual genes of rainbow trout, author estimated a variation ratio of the mean Ct value of the DNA extracted using the comparative CTt method was 37.27, and the standard deviation was 5.33. The correlation coefficient between the Ct values and the concentration of cDNA was -0.98, -0.99, -0.91 and -0.86, respectively (vinculin, AgRP, MC4R I and MC4R II genes). Since this correlation showed high linearity, the straight line obtained was used as a standard for the O. mykiss tissues reared in aquarium. A PCR efficiency of 100% is ideally achieved when the slopes are close to the theoretical value of -3.31. According to quantification method, the results of quantification are strongly affected by the DNA fragmentation. The size of most DNA fragments obtained from various tissues of rainbow trout used in the experiment was approximately 100 bp. According to the four slopes, an efficiency of nearly 100% was estimated for four genes detection methods. Additionally, further analysis with more individuals and primers will be required to fully establish optimization in rainbow trout.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권9호
• /
• pp.981-986
• /
• 2015

지구온난화에 대한 심각성이 대두되면서 선박부문의 온실가스 배출에 관한 연구가 전 세계적으로 활발하게 진행되고 있다. 이에 반하여 국내 연구 수준은 기초에 그치고 있다. 본 논문에서는 선박으로부터 배출되는 이산화탄소의 여러가지 저감대책 중에서 운항손실과 투자비용을 최소화하면서 수행할 수 있는 방법으로 전자제어엔진 사용, 트림 최적화, 프로펠러 연마 및 친환경 방오도료의 사용을 선정하였다. 선정된 저감대책들을 운항실습선에 적용하여 시험 운항을 실시하였고 연료소비율에 미치는 영향을 분석하였다. 그 결과, 각 대책들은 약 1~5%의 연료소비율 저감 효과가 있었고 이를 에너지효율운항지수 산출에 적용하면 약 1~5%를 감소시키는 것을 알 수 있었다. 향후 국제적 환경규제를 제정할 때 우리나라에게 유리하도록 대응하기 위해서는 에너지효율운항지수에 대한 연구에도 지속적인 노력이 필요하다고 사료된다.

• 디지털산업정보학회논문지
• /
• 제12권1호
• /
• pp.1-12
• /
• 2016

The current economic crisis is making new demands on manufacturing industry, in particular, in terms of the flexibility and efficiency of production processes. This requires production and administrative processes to be meshed with each other by means of IT systems to optimise the use and capacity utilisation of machines and lines but also to be able to respond rapidly to wrong developments in production and thus to minimise adverse impacts on the business. The future scenario of the "smart factory" represents the zenith of this development. The factory can be modified and expanded at will, combines all components from different manufacturers and enables them to take on context-related tasks autonomously. Integrated user interfaces will still be required at most for basic functionalities. The complex control operations will run wirelessly and ad hoc via mobile terminals such as PDAs or smartphones. The comnination of IoT, and Big Data optimisation is bringing about huge opportunities. these processes are not just limited to manufacturing, anywhere a supply chain environment exists can benefit from information provided by linked devices and access to big data to inform their decision support. Building a smart factory with smart assets at its core means reaching those desired new levels of productivity and efficiency. It means smart products that leverage advanced traceability, connectivity and intelligence. For businesses, it means being able to address the talent crunch through more autonomous. In a Smart Factory, machinery and equipment will have the ability to improve processes through self-optimization and autonomous decision-making.

• 한국태양에너지학회 논문집
• /
• 제35권2호
• /
• pp.93-101
• /
• 2015

Zero energy building is a self sufficient building that minimizes energy consumption through passive elements such as insulation, high performance window system and installing of high efficiency HVAC system and uses renewable energy sources. The Korea Government has been strengthening the building energy efficiency standard and code for zero energy building. The building energy performance is determined by the performance of building envelope. Therefore it is important to optimize facade design such as insulation, window properties and shading, that affect the heating and cooling loads. In particular, shading devices are necessary to reduce the cooling load in summer season. Meanwhile, BIPV shading system functions as a renewable energy technology applied in solar control facade system to reduce cooling load and produce electricity simultaneously. Therefore, when installing the BIPV shading system, the length of shadings and angle that affect the electricity production must be considered. This study focused on the facade design applied with BIPV shading system for maximizing energy saving of the selected standard building. The impact of changing insulation on roof and walls, window properties and length of BIPV shading device on energy performance of the building were investigated. In conclusion, energy consumption and electricity production were analyzed based on building energy simulations using energyplus 8.1 building simulation program and jEPlus+EA optimization tool.