• Journal of Fisheries and Marine Sciences Education
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• v.6 no.1
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• pp.11-19
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• 1994

The North Pacific midwater trawling which is one of the important fishing methods for Korean fishing industry is working in the Bering Sea and the sea near Kamchaka Peninsula. The catch by Korean midwater trawlers had been recorded about 300 thousands $^{M/_T}$ a year. Six types of midwater trawl net-ordinary midwater trawl net, super-V trawl net, super mesh trawl net, rope trawl net, super plus trawl net and kite trawl net-have been widely used by large trawlers above 1,500gt in size since 1982. Regarding the fishing efficiency, the super plus trawl net and kite trawl net were acknowledged as higher than other nets. Maximum mesh size of super-plus trawl net and kite trawl net ranges about 20m, whereas the length of net about 150m, and high-tech polyethylene is used as the material of rope part. The problems involved in the North Pacific midwater trawl net may be summarized as follows ; (1) The dimension of fishing gear is too big compared with the towing power of trawler. (2) The mesh size of the rope part is too big compared with that of the common netting part. (3) The net is often torn out in the connecting position of the rope part and the netting part. (4) The net is not matched with the trawler and the otter board in many trawlers, so the shape of the trawl gear in the water is instable. (5) The fish school located near head rope, ground rope and side rope in the net recorder is not caught in practice because of the net instability.

• Journal of Broadcast Engineering
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• v.26 no.2
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• pp.167-174
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• 2021

Recently, deep learning technology is widely used in various computer vision applications, such as object recognition, classification, and image generation. In particular, the deep learning-based super-resolution has been gaining significant performance improvement. Fast super-resolution convolutional neural network (FSRCNN) is a well-known model as a deep learning-based super-resolution algorithm that output image is generated by a deconvolutional layer. In this paper, we propose an FPGA-based convolutional neural networks accelerator that considers parallel computing efficiency. In addition, the proposed method proposes Optimal-FSRCNN, which is modified the structure of FSRCNN. The number of multipliers is compressed by 3.47 times compared to FSRCNN. Moreover, PSNR has similar performance to FSRCNN. We developed a real-time image processing technology that implements on FPGA.

• Journal of the Korean Society for Library and Information Science
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• v.15
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• pp.197-224
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• 1988

The kernel technique in game theory is introduced and modified in the notion of super kernel, which creates searching maps through the hierarchic clustering technique. The results show more Improved retrieval efficiency in terms of precision and recall.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.162-162
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• 2010

• Journal of Korea Port Economic Association
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• v.32 no.3
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• pp.1-20
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• 2016

The objective of this study was to select world top 20 major container terminals that belong to Korea and China as comparison units to analyze their efficiency and productivity trend. Super Efficiency Data Envelopment Analysis(SE-DEA) and Malmquist Productivity Index(MPI) models were applied to this study. Compared with previous studies, we narrowed down the scope of the comparison units to terminals and conducted more detailed analysis to present more meaningful implications to the actual operation. The different result from existing studies, SE-DEA analysis implied that the major terminals of Busan New Port showed similar efficiency and productivity with China's terminals. In MPI analysis, the average index of Korean and China's terminals is 1.051 and 1.049. The analysis indicates that the productivity was improved 5.1% and 4.9% annually. From 2012 to 2015, the average terminal TCI index of South Korea and China were 1.032 and 1.0318-the main factor which influences MPI. This means improving productivity mainly rely on investment in new equipment and technology upgrades rather than improve operational efficiency over the past few years. Future management decisions should consider more aggressive marketing to increase the volume and improve operational efficiency to enhance productivity. Further research should apply the overall efficiency of the methodology considering the financial diversification, terminal capacity, service levels, and other factors.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.635-655
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• 2020

The sag effect of long stay cables is one of the key factors restricting further increase in the span of cable-stayed bridges. Based on the formerly proposed concept of long stay cables lifted by an auxiliary suspension cable in cross-strait cable-stayed bridges, corresponding static approximate calculations and analytical theory based on catenary and parabolic cable configurations are established. Taking a main span 1400 m cable-stayed bridge as the research object, three typical lifting conditions and the whole process of auxiliary cable lifting are analyzed and discussed. The results show that the sag effect is effectively reduced. The support efficiency is only improved when the cables are lifted above the original cable chord. Reduction of the horizontal component force of the cable is limited. The equivalent elastic modulus and the vertical support stiffness of the lifted cables are significantly increased with increased horizontal projection length and not sensitive to the change of the lifting point position. The scheme of lifting the cable to the chord midpoint is more economical because of the less steel required for the auxiliary suspension cable, but its effect on improving the vertical support efficiency is limited. The support efficiency is better when the cable is lifted to the cable end tangential to the original cable chord, but the lifting force and the cross-sectional area of the auxiliary suspension cable are doubled. The approximate calculation results of the lifted cables are very close to the numerical analysis results, which verifies the applicability of the approximation method proposed in this study. The results of parabolic approximation calculations are approximately equal to that of catenary cable geometry. As the parabolic approximation analysis theory of lifted cables is more convenient in mathematical processing, it is feasible to use parabolic approximation analysis theory as the analytical method for the conceptual design of lifted cables of super-long span cable-stayed bridges.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.155-159
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• 2000

In the spring silkworm rearing period of year 1998, some nutritional aspects were studied in the Agricultural Research Station of the Komotini town in Greece, to investigate the feeding behaviour of some Bulgarian silkworm hybrids, suitable for spring rearing, during the fourth and fifth instal under the local climatic conditions. The silkworms were fed by locally cultivated Japanese Kinriu mulberry (Morus alba L.) variety leaves. Eight Bulgarian hybrids had been used, namely Vratza-53xVratza-52, Ukraine-20xVratza-53, Super 1xHessa 2, Merefa 2xVratza 35, as well as their reciprocal crosses. The studies showed out a remarkably higher feed intake and feed utilization by the hybrids Hessa 2xSuper-1, Merefa 2xVratza 35 and Vratza-52xVratza-53. The same hybrids showed an efficient food utilization by means of daily growths cocoon shell ratio and raw silk output. In terms of food to silk conversion efficiency Hessa 2xSuper-1 hybrid gave the best results. Larval stage duration for fourth and fifth instar was not affected by feed intake and utilization. All hybrids showed a good adaptation to the local environment and their feeding performance was equal to the international existing standards. All calculated parameters were found to be around the mean values of other up to date presented results and thus considered as acceptable for the needs of the local production.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.329-335
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• 2006

In order to improve thermal efficiency of the fossil fuel power plants, we need to develop advanced materials with superior durability in the ultra-super critical state, which requires surface modifications for superior surface properties. In this study, we coated the Incoloy 901 and 12-17Cr steels for turbine buckets and valves with nitriding, boriding, and $Cr_3C_2-NiCr$ HVOF(high velocity oxygen flow) method. Then the samples were heat treated at $650^{\circ}C$ for 100 hours in vacuum. We analyzed the evolution behaviors of nitrides such as $Fe_3N,\;Fe_4N$, and CrN and borides such as FeB and $Fe_2B$ with XRD and SEM/EDS by comparing hardnesses and compositions of the coated layers before and after the heat treatments.

• Journal of Power System Engineering
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• v.11 no.3
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• pp.22-28
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• 2007

Liquefied gas vaporizer is a machine to vaporize liquefied gas such as liquid nitrogen($LN_{2}$), liquefied natural gas(LNG), liquid oxygen($LO_{2}$) etc. For the air type vaporizer, the frozen dew is created by temperature drop (below 273 K) on vaporizer surface. The layer of ice make a contractions on vaporizer. The structure analysis on the heat transfer was studied to see the effect of geometric parameters of the vaporizer, which are length 1000 mm of various type vaporizer. Structure analysis result such as temperature variation, thermal stress and thermal strain have high efficiency of heat emission as increase of thermal conductivity. As the result, Frist, With-fin model shows high temperature distribution better than without-fin on the temperature analysis. Second, Without-fin model shows double contractions better then with-fin model under the super low temperature load on the thermal strain analysis. Third, Vaporizer fin can be apply not only heat exchange but also a stiffener of structure. Finally, we confirm that All model vaporizer can be stand for sudden load change because of compressive yield stress shows within 280 MPa on thermal stress analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.191-198
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• 2003

Flat slab system has been adopted in many buildings constructed recently because of the advantage of reduced floor heights to meet the economical and architectural demands. Structural engineers commonly use the equivalent frame method(EFM) with equivalent beams proposed by Jacob S. Grossman in practical engineering for the analysis of flat slab structures. However, in many cases, when it is difficult to use the EFM, it is necessary to use a refined finite element model for an accurate analysis. But it would take significant amount of computational time and memory if the entire building structure were subdivided into a finer mesh. An efficient analytical method is proposed in this study to obtain accurate results in significantly reduced computational time. The proposed method employs super elements developed using the matrix condensation technique and fictitious beams are used in the development of super elements to enforce the compatibility at the interfaces of super elements. The stiffness degradation of flat slab system considered in the EFM was taken into account by reducing the elastic modulus of floor slabs in this study. Static and dynamic analyses of example structures were peformed and the efficiency and accuracy of the proposed method were verified by comparing the results with those of the refined finite element model and the EFM.