• Korean Journal of Materials Research
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• v.4 no.5
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• pp.516-523
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• 1994

The interfacial coherency of metal organic chemical vapor deposition grown InGaAsP/InP heterostructure wafers was examined and their influences on the optoelectronic properties were investigated in this study. (400) symmetric and (511) asymmetric reflections were employed to measure the lattice coherency. Existence of misfit dislocations was examined by x-ray topography and reverified by photoluminescence (PL) imaging. PI, measurements were performed, and higher PL intensity was obtained for elastically strained samples and lower intensity for plastically deformed samples. The highest PL intensity was obtained for the sample lattice matched at the growth temperature. PL full-width at half maximum (FWHM) was found to depend on the degree of lattice mismatch. A correlatior between x-ray FWHM and PL intensity was empirically established. The results presented demonstrate that the interfacial coherency is of primary significance in affecting the optoelectronic properties through elastic strain and plastic deformation.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.699-708
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• 2006

Bus splitting technique reduces bus energy by placing modules with frequent communications closely and using necessary bus segments in communications. But, previous bus splitting techniques can not be used in MPSoC platform, because it uses cache coherency protocol and all processors should be able to see the bus transactions. In this paper, we propose a bus splitting technique for MPSoC platform to reduce bus energy. The proposed technique divides a bus into several bus segments, some for private memory and others for shared memory. So, it minimizes the bus energy consumed in private memory accesses without producing cache coherency problem. We also propose a task allocation technique considering cache coherency protocol. It allocates tasks into processors according to the numbers of bus transactions and cache coherence protocol, and reduces the bus energy consumption during shared memory references. The experimental results from simulations say the bus splitting technique reduces maximal 83% of the bus energy consumption by private memory accesses. Also they show the task allocation technique reduces maximal 30% of bus energy consumed in shared memory references. We can expect the bus splitting technique and the task allocation technique can be used in multiprocessor platforms to reduce bus energy without interference with cache coherency protocol.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.5
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• pp.29-35
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• 1994

The microstructual refinement process of Al-5Cr-2Zr alloys mechanical alloying 30h can be divided in five stages ; initial stage, welding predomminance stage, spherical partical formation stage, convolution welding predominance stage, and steady state. The rate of structural of aluminium splats was roughly logarithmic with processing time ; ${\in}$=k/0.78 ln(1+0.0028t). The age hardening in rapidly solidified Al-5Cr-2Zr alloys is ascribed to the coherency and dispersion hardening. Coherency hardening is occurred by matastable cubic Al3Zr precipitates in Al-Cr-Zr alloys. Dispersion hardening after mechanical alloying is attributed to the finely-dispersed $Al_2O_3$ and $Al_4C_3$ in Al-5Cr-2Zr alloys.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.226-229
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• 1989

With the increasing number of power plants in modern electric power systems, power system dynamics studies become more complex. Frequently, only some part of the power system is interesting. So it becomes necessary to reduce the size of dynamics or to introduce the dynamic equivalencing techniques. The major approach of dynamic equivalencing techniques are two: one is coherency approach, which seperates machines in groups and combines machines within each group closely swinging together into one equivalent and the other is modal approach which neglects the fast modes of external system. In this paper, a new dynamic equivalencing approach which seperates machines in coherent groups as the coherency method but doesn't predetermine the structure of the equivalent.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.3
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• pp.74-83
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• 1997

In this paper, a new stereo matching algorithm is proposed which uses th econstrainted optimization technique and the matching measures between the segments extracted from zero-crossing edges. The initial matching measures and average disparities are calculated by the features of segments on the searching window of the left and right images. The matching measure is calculated by applying an exponential function using the differences of slope, overlapped length and intensity. The coherency constraint is that neighbouring image points corresponding to the same object should have nearly the same disparities. The matching measures are iteratively updated by applying the coherency constraint. Simulation results on various images show that the proposed algorithm more acculately extracts the segment disparity.

• KIEE International Transactions on Power Engineering
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• v.12A no.1
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• pp.20-25
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• 2002

This paper deals with the development of dynamic equivalents of the Korea Electric Corporation (KEPCO) systems. Several coherency identification methods are studied in order to find a proper method to well represent the dynamic characteristics of the KEPCO system. Also, this paper presents the comparison of the detail and classical aggregation methods in terms of the dynamic and static characteristics of the system. The nonlinear time simulation of the developed KEPCO equivalent system and the original system is performed to illustrate the validity of the equivalent system.

• Language and Information
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• v.7 no.2
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• pp.59-79
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• 2003

Coordination in natural language is often syntactically explained by the rule schema X \longrightarrow X′ and X", where X′ and X" refer to expressions of a like syntactic type. While this schema does explain a lot of instances of coordination, it is well known that this schema also gives rise to serious structural ambiguity, leading not only to numerous unintended interpretations but also to a high degree of unnecessary computational complexity. In order to identify intended interpretations, we need to take into account a number of clues at all the levels of morphology, syntax, semantics, and pragmatics/discourse. In this paper, we propose, with an accompanying data analysis, principles of symmetry and coherency for an effective and reasonable identification of intended interpretations from coordination-bearing sentences.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.77-86
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• 2008

False sharing is a result of co-location of unrelated data in the same unit of memory coherency, and is one source of unnecessary overhead being of no help to keep the memory coherency in multiprocessor systems. Moreover, the damage caused by false sharing becomes large in proportion to the granularity of memory coherency. To reduce false sharing in page-based DSM systems, it is necessary to allocate unrelated data objects that have different access patterns into the separate shared pages. In this paper we propose sized and call-site tracing-based shared memory allocator, shortly SCSTallocator. SCSTallocator places each data object requested from the different call-sites into the separate shared pages, and at the same time places each data object that has different size into different shared pages. Consequently data objects that have the different call-site and different object size prohibited from being allocated to the same shared page. Our observations show that our SCSTallocator outperforms the existing dynamic shared memory allocators. By combining the two existing allocation technique, we can reduce a considerable amount of false sharing misses.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1339-1353
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• 2004

< TABLE > tags in HTML documents are widely used for formatting layout of Web documents as well as for describing genuine tables with relational information. As a prerequisite for information extraction from the Web, this paper presents an efficient method for sophisticated table detection. The proposed method consists of two phases: preprocessing and attribute-value relations extraction. For the preprocessing where genuine or ungenuine tables are filtered out, appropriate rules are devised based on a careful examination of general characteristics of < TABLE > tags. The remaining is detected at the attribute-value relations extraction phase. Specifically, a value area is extracted and checked out whether there is a syntactic coherency Futhermore, the method looks for a semantic coherency between an attribute area and a value area of a table that may be inappropriate for the syntactic coherency checkup. Experimental results with 11,477 < TABLE > tags from 1,393 HTML documents show at the method has performed better compared with previous works, resulting in a precision of 97.54% and a recall of 99.22% in average.

• Structural Engineering and Mechanics
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• v.36 no.1
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• pp.111-127
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• 2010

This paper studies the effects of spatially varying ground motions on the responses of a bridge frame located on a canyon site. Compared to the spatial ground motions on a uniform flat site, which is the usual assumptions in the analysis of spatial ground motion variation effects on structures, the spatial ground motions at different locations on surface of a canyon site have different intensities owing to local site amplifications, besides the loss of coherency and phase difference. In the proposed approach, the spatial ground motions are modelled in two steps. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function and an empirical spatial ground motion coherency loss function. Then, power spectral density function of ground motion on surface of the canyon site is derived by considering the site amplification effect based on the one dimensional seismic wave propagation theory. Dynamic, quasi-static and total responses of the model structure to various cases of spatially varying ground motions are estimated. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effects, to spatial ground motions without considering coherency loss or phase shift are also calculated. Discussions on the ground motion spatial variation and local soil site amplification effects on structural responses are made. In particular, the effects of neglecting the site amplifications in the analysis as adopted in most studies of spatial ground motion effect on structural responses are highlighted.