• 정보처리학회논문지A
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• 제13A권6호
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• pp.525-532
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• 2006

인과적 메시지 로깅을 위한 기존 회복 알고리즘들에 비해, Elnozahy가 제안한 회복 알고리즘은 안전한 저장소 접근횟수를 매우 줄이고, 회복과정을 수행하는 동안 살아있는 프로세스들이 자신의 계산을 계속해서 수행할 수 있도록 한다. 그러나, 인과적 메시지 로깅 기법이 비동기적 검사점 기록 기법과 함께 사용된다면, 동시적 고장들이 발생하는 경우 이 알고리즘 수행 후 전체 시스템 상태가 일관적이지 못하게 될 수 있다. 본 논문에서는 이러한 일관적이지 못한 경우들을 보여주고, 이러한 문제점을 해결하는 인과적 메시지 로깅을 위한 저 비용의 회복 알고리즘을 제안한다. 시스템 일관성을 보장하기 위해, 이 알고리즘은 회복 리더가 모든 살아있는 프로세스들뿐만 아니라 다른 회복 프로세스들로부터 회복정보를 얻을 수 있도록 한다. 또한, 제안된 알고리즘은 Elnozahy 회복 알고리즘에 비해 어떠한 부가적인 메시지도 요구하지 않으며, 메시지 피기백에 의해 발생되는 제안된 알고리즘의 부가적인 비용이 매우 낮다 이를 입증하기 위해, 시뮬레이션 결과는 제안된 알고리즘이 Elnozahy 알고리즘에 비해 회복정보 수집시간을 단지 1.0%$\sim$2.1% 정도로 증가시킴을 보여준다.

• 한국통신학회논문지
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• 제39A권12호
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• pp.756-763
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• 2014

본 논문에서는 트리검색 기반의 GTMP (matching pursuit with greedy tree search)이라는 새로운 희소신호 복원기법을 제안한다. 트리검색은 비용함수 (cost function)를 최소화함으로써 희소신호 복원 성능을 향상시키기 위해 적용하였다. 또한 각 노드마다 트리제거 (tree pruning)기법을 이용하여 효율적인 알고리듬을 개발하였다. 본 논문에서는 알고리듬의 성능분석을 통해 희소신호에서 영(0)이 아닌 값의 위치를 정확히 찾아내는 조건을 도출하였다. 그리고 실험을 통해 GTMP가 기존의 희소신호 복원기법에 비해 성능이 향상되었음을 보였다.

• 한국폐기물자원순환학회지
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• 제35권8호
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• pp.762-769
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• 2018

This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.

• 상하수도학회지
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• 제28권4호
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• pp.473-478
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• 2014

Microalgae is known as one alternative energy source of the fossil fuel with the small size of $5{\sim}50{\mu}m$ and negative charge. Currently, the cost of microalgae recovery process take a large part, about 20 - 30% of total operating cost. Thus, the microalgae recovery method with low cost is needed. In this study, the optimum current for Scenedesmus dimorphus recovery process using electrocoagulation techniques was investigated. Under the electrical current, Al metal in anode electrode is oxidized to oxidation state of $Al^{3+}$. In the cathode electrode, the water electrolysis generated $OH^-$ which combine with $Al^{3+}$ to produce $Al(OH)_3$. This hydroxide acts as a coagulant to harvest microalgae. Before applying in 1.5 L capacity electrocoagulation reactor, Scenedesmus dimorphus was cultured in 20 L cylindrical reactor to concentration of 1 OD. The microalgae recovery efficiency of electrocoagulation reactor was evaluated under different current conditions from 0.1 ~ 0.3 A. The results show that, the fastest and highest recovery efficiency were achieved at the current or 0.3 A, which the highest energy efficiency was achieved at 0.15 A.

• 방사성폐기물학회지
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• 제16권3호
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• pp.369-376
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• 2018

The ability to recover the nearly limitless supply of uranium contained within the world's oceans would provide supply security to uranium based fuel cycles. Therefore, in addition to U.S. national laboratories conducting R&D on a system capable of harvesting seawater uranium, a number of collaborative university partners have developed alternative technologies to complement the national laboratory scheme. This works summarizes the systems analysis of such novel uranium recovery technologies along with their potential impacts on seawater uranium recovery. While implementation of some recent developments can reduce the cost of seawater uranium by up to 30%, other researchers have sought to address a weakness while maintaining cost competitiveness.

• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.670-678
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• 1999

Heat recovery steam generator(HRSG) is a principal component of the combined cycle power plant (CCPP) which utilizes the waste energy of the gas turbine exhaust gas. A design of the HRSG is a keypoint to achieve high cycle efficiency with competitive cost. This paper presents a brief review on the design of a HRSG which covers the basic design parameters and their effects on the performance and the investment cost. Finally the concept of the optimum design point is presented according to the selection of a pinch point temperature difference and a steam pressure as an illustrated case.

• Membrane and Water Treatment
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• 제8권5호
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• pp.411-421
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• 2017

Forward osmosis (FO) is an emerging technology which can possibly make the desalination process more cost and energy efficient. One of the major factors impeding its growth is the lack of an appropriate draw solute. The present study deals with the identification of potential draw solutes, and rank them. The comparison was carried out among ten draw solutes on the basis of four main parameters namely; water flux, reverse salt diffusion, flux recovery and cost. Each draw solute was given three 24 hour runs; corresponding to three different concentrations; and their flux and reverse salt diffusion values were calculated. A fresh membrane was used every time except for the fourth time which was the flux recovery experiment conducted for the lowest concentration and the change of flux and reverse salt diffusion values from the initial run was noted. The organic solutes inspected were urea and tartaric acid which showed appreciable values in other parameters viz. reverse salt diffusion, flux recovery and cost although they generated a lower flux. They ranked 5th and 8th respectively. All the experimented draw solutes were ranked based on their values corresponding to each of the four main parameters chosen for comparison and Ammonium sulfate was found to be the best draw solute.

• 한국측량학회지
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• 제26권3호
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• pp.293-301
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• 2008

본 연구는 국가에서 많은 예산을 투입하여 구축한 KLIS 자료의 가격 산출에 목적이 있다. 이를 위해 가격 투입된 원가 분석을 수행하였으며, 판매량 및 회수율을 고려한 판매가와 정보량을 기준으로 한 판매가격을 산출하였다. 회수율을 고려했을 경우 많은 구임비용이 소요되었지만 정보량을 기준으로 하였을 경우에는 적은 비용이 소요되어 지리정보 활성화 측면을 고려하였을 때 정보량을 기준으로 하는 것이 타당함을 알 수 있었다.

• 대한토목학회논문집
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• 제37권3호
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• pp.611-619
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• 2017

본 연구는 대체수자원시설 - 해수담수화, 식수용저수지, 용수전용댐, 지하댐, 그리고 두 개의 간접취수 방법인 강변여과와 청정지하저수지 - 을 고려한 다양한 용수공급시스템별 음용수 단위생산단가를 산정하기 위한 종합적인 방법과 분석결과를 제시한다. 대체수자원시설 건설부터 도수관로를 거쳐 후처리시설을 통한 음용수 생산 지점까지의 모든 건설비용과 운영관리비를 반영하기 위하여 필요한 데이터를 취합하고 개별 총사업비와 운영관리비 추정모델을 개발하였다. 단위생산단가에 영향을 주는 후처리시설과 도수관리의 길이, 그리고 음용수 생산용량에 대한 민감도 분석결과 청정지하저수지가 가장 비용이 작은 대체수자원시설로 분석되었으며 개별 대체수자원시설과 다양한 용수공급시스템별 경제성 정보는 수자원시설 계획 및 예산 분배 의사결정을 지원할 것으로 예상한다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1193-1196
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• 2007

A new planar transformer type energy recovery circuit for PDP is proposed in this paper. The same current is transferred through both the primary and secondary sides during the energy recovery period. The conduction loss is reduced. Fabrication through simple manufacturing processes is possible using the PCB winding.