• 한국기계가공학회지
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• 제7권1호
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• pp.53-61
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• 2008

In this research, the layout and geometry of U-type ribs in the part, including significant process conditions, are automatically optimized to reduce part warpage with robustness in consideration. The optimization procedure are based on an iterative redesign methodology integrated with computer aided injection molding simulation, Taguchi's Design of Experiment(DOE), and a direct search-based optimization method. The robustness of a design alternative is efficiently measured by introducing composite noise factor and Taguchi's signal-to-noise ratio. As a solution search methodology, the modified design space reduction method based on orthogonal arrays is employed to exploit an optimal robust design alternative. To illustrate the proposed methodology, a case study is performed on simulation results, where an optimal robust design alternative is obtained with a moderate number of iterations.

• 호남수학학술지
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• 제46권1호
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• pp.12-37
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• 2024

The paper introduces a set of new ruled surfaces such that the base curve is taken to be the striction curve of N, C and W ruled surfaces from the alternative frame, and the generating line is taken to be one of the vectors of Sannia frame. The characterizations for each ruled surface such as fundamental forms, the Gaussian and mean curvature are also examined to provide the conditions for each surface to be developable or minimal.

• 한국해양공학회지
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• 제35권1호
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• pp.1-12
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• 2021

As increasing the international community's awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries' size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future.

• Weed & Turfgrass Science
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• 제6권3호
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• pp.235-248
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• 2017

본 연구는 $5-25^{\circ}C$ 조건의 자연실온에서 훼스큐 초종 간 발아력, 발아세 및 발아 피크 기간을 조사하고자 수행되었다. 자연 실온 환경에서 종자 발아력은 62.0-97.0% 사이로 나타났는데 가장 우수한 초종은 TF 'Olympic Gold' 품종으로 나타났다. 초종 간 종자 발아력은 광엽형인 TF 초종이 세엽형 보다 더 우수하였으며, 세엽형 훼스큐 초종 간 발아력은 SF>CF, HF>CRF 순서로 나타났다. 발아세의 경우 발아율이 50%에 도달할 때까지 소요되는 50% 발아세 속도부터 80% 발아세 속도까지 전체적인 초종 간 발아세 경향은 TF 초종이 가장 빨랐고 TF 다음으로는 CF 초종 이었다. 그리고 HF 및 SF 초종은 발아세 속도가 중간 정도로 나타났고, 훼스큐 속에서 발아세 속도가 가장 느린 초종은 CRF로 판단되었다. 하지만 발아환경에 따른 50% 및 70% 발아세 경향은 자연실온($5-25^{\circ}C$)보다는 ISTA 변온($15-25^{\circ}C$)에서 평균 약 4일 정도 더 빨랐으며, 실무적으로 훼스큐 종자 파종은 낮과 밤의 온도 차이가 ISTA 변온 환경에 근접할수록 바람직한 것으로 판단되었다. 훼스큐 속 초종 간 발아 피크 기간(Peak time II)은 광엽형 TF 품종이 0.73-1.84일, 평균 1.45일로 세엽형 품종 보다 더 짧게 나타났다. 그리고 세엽형 훼스큐 초종 간 발아 피크 기간은 2.16-11.15일 사이로 다양하였는데 SFCF>SF>HF>CRF 순서로 판단되었다. 전체 공시 품종에서는 TF 'Olympic Gold' 품종이 가장 우수하였고, 반대로 CRF 'Audubon' 품종이 가장 불량한 것으로 판단되었다. 즉 훼스큐 속 초종 및 품종에 따라 이러한 조성 속도 및 특성 차이가 크게 나타날 수 있기 때문에 잔디밭 조성 시 적절한 초종 및 품종 선택은 대단히 중요하다.

• 한국환경복원기술학회지
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• 제12권3호
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• pp.72-82
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• 2009

Research was initiated to investigate early establislment characteristics and germination pattern of perennial ryegrass (PR, Lolium perenne L.). Eight varieties of PR were evaluated in the study. An alternative environmental condition for a PR germination test required by International Seed Testing Association (ISTA) was applied in the experiment, consisting of 8-hr light at $25^{\circ}C$ and 16-hr dark at $15^{\circ}C$ (ISTA conditions). Daily and cumulative germination pattern were measured and analyzed daily for 30 days. Significant differences were observed in germination pattern, days to the first germination, days to 50% germination, days to 75% germination, and final germination rate. Germination rates were variable among the varieties, being 66.00 to 93.75% at the end of study. There were considerable variations in early germination characteristics and germination pattern among PR varieties. The first germination in all entries tested was initiated from 3 to 5 DAS (days after seeding) under ISTA conditions, being 2 days in differences among the varieties. It was 4 to 7 DAS in days to the 50% germination, being 1 to 3 days later from the first germination and three days were variable among them. Days to the 75% germination were 5.93 to 10.50 DAS under ISTA conditions, being 4.57 days in variety differences. Pennant II and Brightstar II were the fastest varieties. The slowest ones were Revenge GLX and Brightstar SLT. Considering days to the first germination, days to 75% germination, and germination pattern etc, Pennant II and Brightstar II were regarded as excellent varieties under ISTA conditions. From tills study, information on differences in germination characteristics and pattern would be usefully applied for golf course design and construction, when established with PR.

• 교육시설
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• 제15권1호
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• pp.53-61
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• 2008

Under recent educational and social backgrounds, alternative education schools are increasing continuously, to compare Japanese example that experience of similar circumstance given before with the investigation of general present condition, specialized education contents, facilities and utilization of 5 schools of Tokyo area, I could know following contents ; First, free schools of Tokyo area were operated by individual education type that consider each student's special quality maximum comparing with Korea's alternative schools which seek community education type. Second, there were not many schools which prescribe school personal allowance per division or class comparing with our cases that operate divides step by equal class with general school and prescribes personal allowance by class, and whole students are generally about $20{\sim}30$. Third, comparing with our cases that are located in mountain and rural area according to profitable locational conditions for environment and experience studying, it was general which islocatedin downtown for the purpose of free attending school of non attending school students. Fourth, usually, comparing with our that unused schools in mountain and rural area are general for alternative school and there were a lot of cases that uses small building of downtown such as lease office, unused warehouse and factory for free school of Tokyo area.

• 대한기계학회논문집B
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• 제22권7호
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• pp.966-979
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• 1998

Thermodynamic and dynamic analysis has been conducted to investigate performance variations induced by substitution of alternative refrigerants, HFC134a or HC600a for CFC12 in hermetic reciprocating compressors. For the thermodynamic analysis, mass and energy conservation laws are applied to the cylinder volume and Helmholtz resonator modeling method is adopted to describe gas pulsations at suction and discharge system. The modeling of the dynamics of the compressor mechanism has been performed with lumped mass method to analyse the bearing loads and friction losses at each bearing. To verify the correctness of this analysis, results of the performance simulation have been compared to those of calorimetric measurrements of compressor operating with CFC12. Analysis of the various losses, noise and reliability as well as performance has been conducted to present the design guideline for the compressor development with alternative refrigerants. It is found that compressors with alternative refrigerants, HFC 134a or HC600a give better COPs than those with CFC12 under the same operating conditions and especially, compressors with HC600a show better reliability and noise characteristics also.

• Molecules and Cells
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• 제46권1호
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• pp.57-64
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• 2023

In eukaryotic cells, a key RNA processing step to generate mature mRNA is the coupled reaction for cleavage and polyadenylation (CPA) at the 3' end of individual transcripts. Many transcripts are alternatively polyadenylated (APA) to produce mRNAs with different 3' ends that may either alter protein coding sequence (CDS-APA) or create different lengths of 3'UTR (tandem-APA). As the CPA reaction is intimately associated with transcriptional termination, it has been widely assumed that APA is regulated cotranscriptionally. Isoforms terminated at different regions may have distinct RNA stability under different conditions, thus altering the ratio of APA isoforms. Such differential impacts on different isoforms have been considered as post-transcriptional APA, but strictly speaking, this can only be considered "apparent" APA, as the choice is not made during the CPA reaction. Interestingly, a recent study reveals sequential APA as a new mechanism for post-transcriptional APA. This minireview will focus on this new mechanism to provide insights into various documented regulatory paradigms.

• Journal of applied mathematics & informatics
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• 제31권5_6호
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• pp.877-894
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• 2013

In this paper, we study the existence and uniqueness of solutions for a singular system of nonlinear fractional differential equations with integral boundary conditions. We obtain existence and uniqueness results of solutions by using the properties of the Green's function, a nonlinear alternative of Leray-Schauder type, Guo-Krasnoselskii's fixed point theorem in a cone. Some examples are included to show the applicability of our results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.564-568
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• 1998

All elements and systems of electronics have optimum temperature conditions. A using of the thermoelectric method of cooling is the most approach for the thermal management of power electronics. An analysis of using the thermoelectric cooling and the temperature control is given as an efficient method of ensuring a work of power electronic devices in conditions of micro-miniaturization.