• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.357-362
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• 2020

The TMFT, a sub-system of TINC, provides voice calls, data transmission and reception, and multimedia services to individual users. At the time of development in 2011, the power circuit of the TMFT was designed to electrical power supply to each device via a charger IC. However, the newly improved power supply circuit allows power to be supplied to each device through the PMIC without configuring the charger IC separately. In this paper, the power circuit design structure of TMFT applied in the development stage and the improved power circuit design structure were compared. And we verified through experiments whether the improved power circuit can be applied to TMFT. The experimental method was verified by directly comparing the current consumption test, charge time comparison test, and rising temperature test during charging each of before and after improvement terminals.

• LP가스
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• s.85
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• pp.22-33
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• 2003

백승홍의원이 발의해 주진되던 LPG법개정안이 협회의 반대로 국회통과가 무산됐다. 협회는 백승홍의원의 LPG법개정안은 유통단계를 고착화시켜 판매사업자의 가격회포에 따른 소비자피해가 우려되며, 정부의 규제완화와 경쟁촉진에도 맞지 않으며, 사업자간 담합 우려, 소비자의 선택권 제한, 기존 판매사업자에 대한 특혜시비 등 여러가지 문제점이 있음을 지적하고 백의원측과 산업자원부에 제출한 바 있다. 협회는 또한 국회 산업자원위원들에게도 동 내용을 전달했으며 충전사업자의 서명을 반대하는 등 꾸준히 반대의견을 개진했었다.

• Journal of Korea Foundry Society
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• v.22 no.6
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• pp.299-303
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• 2002

수정된 SIMPLE법과 VOF의 결합으로 predictor-two step corrector-VOF라고 불리는 새로운 알고리즘이 주조 시 용탕 충전과정을 해석하기 위해 개발되었다. 운동량보존으로부터 유도된 새 2단계 속도 경계조건 처리법은 용탕의 자유표면을 추적하는 데 사용되었다. 본 연구에서는 2개의 예제 계산을 통해 계산정확도와 속도에 대한 Courant 수의 영향을 살펴보았다. 그 결과 적당한 Courant 수의 증가는 계산 정확도의 감소 없이 용탕 계산 속도를 향상시킬 수 있는 것으로 나타났다. 또한 만족할 만한 계산 정확도와 효율이 이 알고리즘의 실제 제품 해석을 통해 얻어졌다.

• Electronics and Telecommunications Trends
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• v.25 no.3
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• pp.89-98
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• 2010

스마트그리드(smart grid)는 발전-송전 배전-판매의 단계로 이루어지던 기존의 단방향 전력망에 IT 기술을 접목하여 전력 공급자와 소비자가 양방향으로 실시간 정보를 교환함으로써 에너지 효율을 최적화하는 지능형 전력망이다. 에너지와 IT의 대표적 융합사례로써 전력망의 선뢰성, 효율성, 안정성을 향상시키고, 전기자동차 충전을 지능화하고 재생에너지와 전력계통 연계를 용이하게 하여 재생에너지 보급을 촉진시켜 준다. 본 고에서는 주요 국가의 스마트그리드 관련 정책 동향을 분석하고 결론에서 우리에게 주는 시사점을 도출하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.519-529
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• 2009

Fiber reinforced composite materials have various advantages in mechanical and chemical aspects. Not only high fatigue and chemical resistance, but also high specific strength and stiffness are attained, and therefore, damping characteristics are beneficial to marine piles. Since piles used for marine structures are subjected to compression and bending as well, detailed research is necessary. Current study examine the mechanical behavior under flexural and/or compressive loads using concrete filled fiber reinforced plastic composite piles, which include large size diameter. 25 pile specimens which have various size of diameters and lengths were fabricated using hand lay-up or filament winding method to see the effect of fabrication method. The inner diameters of test specimens ranged from 165 mm to 600 mm, and the lengths of test specimens ranged from 1,350 mm to 8,000 mm. The strengths of the fill-in concrete were 27 and 40 MPa. Fiber volumes used in circumferential and axial directions are varied in order to see the difference. For some tubes, spiral inner grooves were fabricated to reduce shear deformation between concrete and tube. It was observed that the piles made using filament winding method showed higher flexural stiffness than those made using hand lay-up. The flexural stiffness of piles decreases from the early loading stage, and this phenomenon does not disappear even when the inner spiral grooves were introduced. It means that the relative shear deformation between the concrete and tube wasn't able to be removed.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.384-388
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• 2000

일반적으로 흡착분리공정 기술개발은 대략 3단계의 과정을 거치게 되는데 흡착제의 선정, 흡착탑의 거동해석, 연속공정 구성 및 운전으로 이루어진다. 이중 흡착제의 선정은 대상 혼합물에 어떤 흡착제를 사용하여 효율적인 분리 결과를 얻을 수 있는가를 결정하는 기초단계이면서도 가장 중요한 과정이다. 이를 위해 여러 흡착제에 대한 흡착평형량과 이로부터 얻어지는 선택도, 흡착열, 그리고 흡착질과 흡착제 사이의 물질전달저항과 흡착제의 기공 분포도, 기공부피, 기공율, 비표면적, 충전 밀도(Bulk Density), 파쇄 강도 및 마모저항 등과 같은 물리적 특성을 종합적으로 비교 검토하여 흡착제를 선택하여야 한다. (중략)

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.558-564
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• 1993

The drying characteristics of fluidized bed drying with different drying conditions using naked barley were carried out. This fluidized drying mechanism of naked barley was consisted of consecutive two falling rate parts, first falling rate period and second falling rate period without showing constant rate period. The drying rate constant was increased with decreasing charged amount and relative humidity and increasing air temperature and air velocity. Since the drying rate constant expressed by Arrhenius type equation in the falling rate period showed good linearity, the falling rate period was considered as the controlling step. The activation energy of first falling step was 1,900 cal/gmol, while for second falling step the values showed 2,500 cal/gmol.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.23-29
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• 2018

A stand-alone Photovoltaic (PV) system is one of the most important energy system for Mongolian nomadic herders. Basically, a stand-alone PV system uses two DC-DC converters. This makes the system costly, size bigger and difficult to move from one place to another place for the nomadic herders. A combined control algorithm for charging the battery using Stage of Charge (SOC) and Maximum Power Point Tracking (MPPT) is proposed in this paper. The batteries are charged by the three stage method; bulk, absorption and float charge. In the bulk stage used the MPPT function in this study. The performance of the proposed control algorithm is evaluated in both steady and changing weather conditions. The results are obtained using PSIM software. The results obtained in this paper are useful in designing a stand-alone PV system in the rural life like Mongolian nomadic herders.

• Composites Research
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• v.12 no.2
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• pp.70-81
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• 1999

Resin transfer molding(RTM) as a composite manufacturing process is currently of great interest in the aerospace industry requiring high performance composite parts. In this study, an analysis of mold filling in the RTM process was carried out by numerical simulation using finite element/control volume technique. Experimental work for the visualization of resin flow through fibrous preform was also conducted in order to quantitatively measure the permeabilities of the fiber mats and to evaluate the validity of the developed numerical code. The different types of fiber mats and silicon oils were selected as reinforcements and resin materials, respectively. The effects of fibrous preform structure, mold geometry, and preplaced insert on the flow front patterns during mold filling were examined by integrating the model predictions and experimental results. The flow fronts predicted by numerical simulation were in good agreement with those observed experimentally. However, according to the regions of the mold, some deviations between predicted and observed flow fronts could be found because of non-uniform fiber volume fraction. Weldline locations for the resin flow through round insert preplaced in the mold could be qualitatively deduced based on predicted flow fronts.

• Fire Science and Engineering
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• v.25 no.5
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• pp.76-84
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• 2011

Steel beams are one of primary member and those carries the horizontal load and floor load to axial member. To avoid structural failure when the steel beams are exposed to fire, fire resistance performance requires. Till now, the evaluation for fire resistance of the beam was conducted using the maximum load and standard fire curve defined in the KS F 2257. But recently the constructional patterns are changing toward multi-function performance to get a better structural performance and fire resistance as well. In this paper to get the databases for fire resistance, limiting temperatures of the beam, load-bearing fire tests according to load ratios, two grades of compressive concrete strengths were applied.