• 한국분말재료학회지
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• 제15권5호
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• pp.399-404
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• 2008

Spray pyrolysis was applied to prepare $M_{3}MgSi_{2}O_{8}:Eu^{2+}$ (M=Ca, Sr, Ba) blue phosphor powder. The library of a Ca-Sr-Ba ternary system was obtained by a combinatorial method combined with the spray pyrolysis in order to optimize the luminescent property under vacuum ultraviolet (VUV) excitation. 10 potential compositions were chosen from the first screening. The emission shifted to longer wavelength as Ca became a dominant element and the emission intensity was greatly reduced in the composition region at which Ba is dominant element. On the base of the first screening result, the second fine tuning was carried out in order to optimize the luminescence intensity under VUV excitation. The optimal composition for the highest luminescence intensity was $(Ca_{1.7},\;Sr_{0.3},\;Ba_{1.0})Si_{2}O_{8}:Eu^{2+}$ which had the color coordinate of (0.152, 0.072) and about 64% emission intensity of $BaMgAl_{10}O_{17}$ (BAM) phosphor.

• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.613-616
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• 2011

Streptomyces venezuelae YJ028, bearing a deletion of the entire biosynthetic gene cluster encoding the pikromycin polyketide synthases and desosamine biosynthetic enzymes, was used as a bioconversion system for combinatorial biosynthesis of glycosylated derivatives of tylosin. Two engineered deoxysugar biosynthetic pathways for the biosynthesis of TDP-3-O-demethyl-D-chalcose or TDP-L-rhamnose in conjunction with the glycosyltransferaseauxiliary protein pair DesVII/DesVIII were expressed in a S. venezuelae YJ028 mutant strain. Supplementation of each mutant strain capable of producing TDP-3-O-demethyl-D-chalcose or TDP-L-rhamnose with tylosin aglycone tylactone resulted in the production of the 3-O-demethyl-D-chalcose, D-quinovose, or L-rhamnose-glycosylated tylactone.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.2811-2830
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• 2017

In this paper, we study the problem of mobile data offloading for a network that contains multiple mobile network operators (MNOs), multiple WiFi or femtocell access points (APs) and multiple mobile users (MUs). MNOs offload their subscribed MUs' data traffic by leasing the unused Internet connection bandwidth of third party APs. We propose a combinatorial auction-based two-stage matching mechanism comprised of MU-AP matching and AP-MNO matching. The MU-AP matching is designed to match the MUs to APs in order to maximize the total offloading data traffic and achieve better MU satisfaction. Conversely, for AP-MNO matching, MNOs compete for APs' service using the Nash bargaining solution (NBS) and the Vickrey auction theories and, in turn, APs will receive monetary compensation. We demonstrated that the proposed mechanism converges to a distributed stable matching result. Numerical results demonstrate that the proposed algorithm well capture the tradeoff among the total data traffic, social welfare and the QoS of MUs compared to other schemes. Moreover, the proposed mechanism can considerably offload the total data traffic and improve the network social welfare with less computation complexity and communication overhead.

• 한국정밀공학회지
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• 제32권8호
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• pp.755-760
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• 2015

For proper wound healing, dermal contraction and remodeling are critical; during the natural healing process, differentiated fibroblasts called "myofibroblasts" typically undertake these functions. For severe wounds, however, a critical mass of dermal matrix and fibroblasts are lost, making self-regeneration impossible. To overcome this impairment, synthetic wound patches with embedded functional cells can be used to promote healing. In this study, we developed a polydioxanone (PDO)-based cell-embedded sheet on which dermal fibroblasts were cultured and induced for differentiation into myofibroblasts, whereby the following combinatorial physicochemical stimuli were also applied: aligned topology, electric field (EF), and growth factor. The results show that both the aligned topology and EF synergistically enhanced the expression of alpha smooth-muscle actin (${\alpha}$-SMA), a key myofibroblast marker. Our proof-of-concept (POC) experiments demonstrated the potential applicability of a myofibroblast-embedded PDO sheet as a wound patch.

• Journal of Electrical Engineering and Technology
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• 제6권2호
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• pp.174-181
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• 2011

This paper proposes a novel binary ant colony optimization (NBACO) method. The proposed NBACO is based on the concept and principles of ant colony optimization (ACO), and developed to solve the binary and combinatorial optimization problems. The concept of conventional ACO is similar to Heuristic Dynamic Programming. Thereby ACO has the merit that it can consider all possible solution sets, but also has the demerit that it may need a big memory space and a long execution time to solve a large problem. To reduce this demerit, the NBACO adopts the state probability matrix and the pheromone intensity matrix. And the NBACO presents new updating rule for local and global search. The proposed NBACO is applied to test power systems of up to 100-unit along with 24-hour load demands.

• 산업공학
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• 제10권2호
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• pp.1-13
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• 1997

The problem of the formation of machine-part cells in FMS is a very important issue at the planning and operating stages of FMS. This problem is inherently a combinatorial optimization problem, proven to be NP-complete(or, NP-hard). Among the several kinds of approaches which have been applied to solve the combinatorial optimization problems, the Simulated Annealing(SA) algorithm, a technique of random search type with a flexibility in generating alternatives, is a powerful problem solving tool. In this paper, the SA algorithm is used to solve machine cell-part family formation problems. The primary purpose of the study is to find the near-optimal solution of machine cell-part family formation problem, whare the product volume and number of operations are prespecified, that can minimize the total material handling cost caused by exceptional elements and intercell moves as much as possible. The results show that the SA algorithm is able to find a near-optimal solution for practical problems of the machine cell-part family formation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.124.2-124.2
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• 2011

현재 박막형 태양전지는 실리콘계가 주류를 이루고 있으며, 유리기판 또는 유연성 기판에 비정질 실리콘 박막을 형성시킨 태양전지와 실리콘 기판 양면에 태양전지를 형성하는 방법 등 효율을 극대화시킨 이종접합 태양전지 등이 연구되고 있다. 예컨대 밴드갭이 서로 다른 박막들 간의 이종접합을 이용한 tandem 구조 및 triple 구조의 Si 박막 태양전지의 경우 13%대 변환효율을 나타낸다고 보고된 바 있다. 본 연구에서는 비정질 Si 박막 태양전지 내 흡수층의 효율을 최대화하기 위하여 AZO/Ag 이중구조 박막의 특성에 관한 연구를 수행하고자 한다. combinatorial sputtering system을 이용하여 AZO/Ag 이중구조 박막을 제작하였으며 타겟으로는 4-inch target(Ag, 2wt% Al2O3 doped ZnO)이 사용되었다. 유리기판 상에 combinatorial sputter system으로 상온에서 제작된 Ag 박막의 두께는 25nm로 성장시켰으며 연속공정으로 AZO 박막을 제작하였고, AZO 박막은 100~500nm의 두께경사를 나타내었다. 이 때 유리기판상에 성장된 Ag/AZO 박막의 면저항은 약 $2{\Omega}/{\Box}$ 값을 나타내었다. 본 발표에서는 AZO/Ag 이중 구조 박막의 우수한 전기적 특성을 기반으로 표면 거칠기 및 반사도 특성 등에 관하여 추가적으로 토론한다.

• Journal of Microbiology and Biotechnology
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• 제19권8호
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• pp.792-802
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• 2009

Antimicrobial peptides (AMPs) are considered to be a promising alternative to conventional antibiotics for future generations. We identified four novel hexapeptides with antimicrobial activity: KCM11 (TWWRWW-$NH_2$), KCM12 (KWRWlW-$NH_2$), KCM21 (KWWWRW-$NH_2$), and KRS22 (WRWFIH-$NH_2$), through positional scanning of a synthetic peptide combinatorial library (PS-SCL). The ability of these peptides to inhibit the growth of a variety of bacteria and unicellular fungi was evaluated. KCM11 and KRS22 preferentially inhibited the normal growth of fungal strains, whereas KCM12 and KCM21 were more active against bacterial strains. Bactericidal activity was addressed in a clear zone assay against phytopathogenic bacteria, including Pectobacterium spp., Xanthomonas spp., Pseudomonas spp., etc. KCM21 showed the highest activity and was effective against a wide range of target organisms. Application of KCM21 with inoculation of Pectobacterium carotovorum subsp. carotovorum on detached cabbage leaves resulted in an immune phenotype or a significant reduction in symptom development, depending on the peptide concentration. Cytotoxicity of the four hexapeptides was evaluated in mouse and human epithelial cell lines using an MTT test. The results revealed a lack of cytotoxic effects.

• 한국농공학회지
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• 제45권6호
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• pp.83-95
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• 2003

In this study, a new concept in a paddy consolidation project is introduced in that curved parallel terracing with contour-lined layout is adopted in sloping areas instead of conventional rectangular terracing. The contoured layout reduces earth-moving considerably compared to rectangular methods in consolidation projects. The objective of the paper is to develop a combinatorial optimization model using the network theory for the design of contour-lined plots which minimizes the volume of earth moving. The results showed that as the length of short side of plot is longer or the land slope is steeper, the volume of earth moving for land leveling increases. The developed optimization model is applied for three consolidated districts and the resulting optimal earth moving is compared with the volume of earth from the conventional method. The shorter is the minimum length of short side of a polt with increases the number of plots, the less is the volume of earth. As the minimum length of short side is 20 m for efficient field works by farm machinery, the volume of earth moving of optimal plot is less by 21.0∼27.1 % than that of the conventional consolidated plots.

• Structural Engineering and Mechanics
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• 제25권2호
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• pp.239-268
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• 2007

This paper deals with optimal stacking sequence design of laminate composite structures. The stacking sequence optimisation of laminate composites is formulated as a combinatorial problem and is solved using Simulated Annealing (SA), an algorithm devised based on inspiration of physical process of annealing of solids. The combinatorial constraints are handled using a correction strategy. The SA algorithm is strengthened by embedding Tabu search in order to prevent recycling of recently visited solutions and the resulting algorithm is referred to as tabu embedded simulated Annealing (TSA) algorithm. Computational performance of the proposed TSA algorithm is enhanced through cache-fetch implementation. Numerical experiments have been conducted by considering rectangular composite panels and composite cylindrical shell with different ply numbers and orientations. Numerical studies indicate that the TSA algorithm is quite effective in providing practical designs for lay-up sequence optimisation of laminate composites. The effect of various neighbourhood search algorithms on the convergence characteristics of TSA algorithm is investigated. The sensitiveness of the proposed optimisation algorithm for various parameter settings in simulated annealing is explored through parametric studies. Later, the TSA algorithm is employed for multi-criteria optimisation of hybrid composite cylinders for simultaneously optimising cost as well as weight with constraint on buckling load. The two objectives are initially considered individually and later collectively to solve as a multi-criteria optimisation problem. Finally, the computational efficiency of the TSA based stacking sequence optimisation algorithm has been compared with the genetic algorithm and found to be superior in performance.