• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.9
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• pp.496-504
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• 2009

In order to investigate the feasibility of a direct ice slurry transporting system for the purpose of district cooling, a case study of field application is performed. The research aims include the field measurement of ice packing factor, the performance of coldness delivery, and the branching characteristics of ice slurry. Two representative types of pipe branch are dealt with in this work. For the slurry flow with ice volume fraction of 0.16 or less, the pipe blocking due to aggregation is not observed. Based on the time-wise variation of temperature in the storage tank, a calculating method of ice packing factor is newly developed, which seems to be useful when the brine concentration is unknown. It is confirmed that the mass flow rate of ice slurry per unit cooling load is markedly reduced with increasing the ice content. The pumping power also decreases, but remains unchanged for high ice fractions. The distribution of ice particle before and after branching shows a good uniformity within the range of 5% difference, but yields a unique trend depending on the flow rate.

• Polymer(Korea)
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• v.36 no.4
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• pp.440-447
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• 2012

The branched copolyester was synthesized and its molecular weight, $T_g$, 1/2 method temperature ($T_{1/2}$) and rheological properties were characterized for the application of toner binder. The linear copolyester had low molecular weight and melt elasticity obtained by dimethylterephthalate (DMT), ethylene glycol (EG) and 2,2-bis(4-(2-hydroxypropoxy) phenyl)propane (HPP). The branched copolyesters prepared with various branching agents such as 2-(hydroxymethyl)-2-ethylpropane-1,3-diol (trimethylol propane, TMP), 2,2-bi(hydroxymethyl)-1,3-propanediol (pentaerythritol, PER), 1,2,4-benzenetricarboxylic anhydride (trimellitic anhydride, TMA) and glycerol to improve the physical properties of the linear copolyester. The effect of branching agents on the molecular weight and melt elasticity of the branched copolyester was examined. The branched copolyesters prepared by adding over 15 mol% of branching agent showed relatively high molecular weight and melt elasticity, and $T_{1/2}$ value of $140^{\circ}C$. Therefore, the highly branched copolyesters were deemed suitable as a hot-melt toner of laser print process.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.354-363
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• 1995

We propose a new search method which is based on the precedence relationship between subgoals.The prosed method reducess both the branching factor of and the depth of the search space by making use of the precedence relationship between subgoals, and further improves the efficiency of A.I.search by immediately achieving directly achievable maximal subgoals and immediately performing the directly applicable actions which must be eventually done.The efficiency of our method has been analysed theoretically.We have also implemented a robot planning system equipped with versions of DFID and IDA which are modified by applying our proposed strategies, and experimentally showed the efficiency of our strategy.

• Journal of Korean Institute of Industrial Engineers
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• v.9 no.1
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• pp.3-6
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• 1983

The objective of this paper is to present a new method for the multi-dimensional Knapsack problem. Toyoda method and Loulou and Michaelides method are well known for this problem. The new method introduces a new penalty factor for fast convergence and a branching technique for accurate solutions. The method is tested at IBM370 and shows that the method is slower than Toyoda method, but more accurate than other two methods.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.81-93
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• 1993

The three dimensional(3D) shape reconstruction from two dimensional(2D) cross-sections can be completed through three main phases : the input compilation, the triangular grid formation, and the smooth surface construction. In the input compilation phase, the cross-sections are analyzed to exctract the input data required for the shape reconstruction. This data includes the number of polygonized contours per cross-section and the vertices defining each polygonized contour. In the triangular grid formation phase, a triangular grid, leading to a polyhedral approximations, is constructed by extracting all the information concerning contour links between two adjacent cross- sections and then performing the appropriate triangulation procedure for each contour link. In the smooth surface construction phase, a smooth composite surface interpolating all vertices on the triangular grid is constructed. Both the smooth surface and the polyhedral approximation can be used as reconstructed models of the object. This paper proposes a new method for reconstructing the geometric model of a 3D objdect from a sequence of planar contours representing 2D cross-sections of the objdect. The method includes the triangular grid formation algorithms for contour closing, one-to-one branching, and one-to-many braanching, and many-to-many branching. The shape reconstruction method has been implemented on a SUN workstation in C.

• Journal of the Korean Ceramic Society
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• v.24 no.4
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• pp.313-320
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• 1987

Fracture toughness of hot pressed cordierite-SiC whisker ceramic composites contained up to 40vol.% SiC whiskers were determined by using the indentation crack length(IC), indentation strengthin-bending(IS), and single-edge notched-beam(SENB) methods. The results were compared to stress intensity factor, KB, at the crack branching boundary measured by using the mirror zone radius (MZ) method. IS method seems to provide a more reasonable estimation of fracture toughness than other methods for these composites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3277-3285
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• 1996

In this paper, w designed an opical power distribution device for application to an optical switching and an optical subscriber loop. We fabricated PSG thin film by LPCVD. Based on the measured index of fabricted thin film, rib-type waveguide was transformed to two-dimension by the effective index method and we simulated dispersion property to find asingle-mode condition. We found that the optimum design parameters of rib-type waveguide are:cladding layer of 3.mu.m, core layer of 3.mu.m, buffer layer of 10.mu.m, and core width of 4.mu.m. Each side of the guiding region was etched down to 4.mu.m to shape the core. We used these optimum parameters of the rib-type waveguide with branching angle of 0.5.deg. and simulted the Y-branch waveguide by the BPM simulation. Numerical loss in branching area was claculated to be 0.1581dB and equal to the total loss of the Y-branch. The loss of the fabricated Y-branch waveguide on PSG film ws 1.6dB at .lambda.=1.3.mu.m before annealing but was 1.2dB after annealing at 1000.deg. C for 10 minutes. Consequently, the loss of branching area from 3000.mu.m to 6000.mu.m in the z-direction was 0.8dB, and single-mode propagation was confirmed by measuring the near field pattern. For coupling the fabricated Y-branch waveguide with an optical fiber, we fabricated V-groove which was used as the upholder of optical fiber. An etching angle was 54.deg. and the width and depth of guiding groove was 150.mu.m, 70.mu.m, respectively. The optical fiber is inserted onto V-groove. Both the Y-branch and V-groove were connected through the index matching oil. Coupling loss after connecting Y-branch and the optical fiber on V-groove was 0.34dB and that after injecting index mateching oil was 0.14dB.

• Journal of Biomedical Engineering Research
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• v.18 no.2
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• pp.187-196
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• 1997

The three-dimensional flow analysis using the finite volume method is presented to compare the steady flow characteristics of blood with those of blood substitutes such as water and aqueous polymer solution in an idealized double branching model. The model is used to simlllate the region of the abdominal aorta near the celiac and superior mesenteric branches. Apparent viscosities of blood and the aqueous Separan solution are represented as a function of shear rate by the Carreau model, Water and aqueoiu Separan AP-273 500wppm solution are frequently used as blood substitutes in vitro experiments. Water is a typical Newtonian fluid and blood and Separan solution are non-Newtonian fluids. Flow phenomena such as velocity distribution, pressure variation and wall shear stress distribution of water, blood and polymer solution are quite different due to differences of the rheological characteristics of fluids. Flow phenomena of polymer solution are qualitatively similar to those of blood but the phenomena of water are quite different from those of blood and polymer solution. It is recommended that a lion-Newtonian fluid which exhibits very similar rheological behavior to blood be used in vitro experiments. A non-Newtonian fluid whose rheological characteristics are very similar to those of blood should be used to obtain the meaninylll hemodynamic data for blood flow in vitro experiment and by numerical analysis

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.857-865
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• 2020

This paper presents a method for code generation of UML sequence diagrams based on message patterns. In the sequence diagrams, it is shown that messages are some types of forms typically. This paper classifies according to type as three patterns, and construct meta-information for code generation analysing structural infomation for each patterns. The meta-message of structural information (MetaMessage) is stored in the MetaMessage datastore and the meta-method information from the MetaMessage is stored in the MetaMethod datastore. And then, the structural information of MetaClass and MetaObject is constructed in each datastore too. For each pattern, this paper presents a method for code generation based on the meta information of message patterns and the syntax of target progamming language. Also, branching and looping that has been seldom handled integratedly in the previous works are handled as same as the basic patterns by classifying the branching pattern and the looping pattern for code generation integratedly.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.477-486
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• 2003

In combinatorial auctions buyers nay bid for arbitrary combinations of goods. But determining the winners of combinatorial auctions who maximize the profit of a seller is known to be NP-complete. A branch-and-bound method can be one of practical algorithm for winner determination. However, bid selection heuristics play a very important role in the efficiency of a branch-and-bound method. In this paper, we designed and implemented an algorithm which used a branch-and-bound method and Linear Programming for winner determination in combinatorial auctions. We propose new bid selection heuristics which consider a branching bid and conflicting bids simultaneously to select a branching bid in the algorithm. In addition, upper bounds are reused to reduce the running time in specific cases. We evaluated the performance of the algorithm by experiments with five data distributions and compared our method with others. The algorithm using heuristics showed a superior efficiency in two data distributions and a similar efficiency in three distributions.