• Proceedings of the KWS Conference
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• 2010.05a
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• pp.51-51
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• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.7
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• pp.29-38
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• 2009

In this paper, a high performance pipelined computing design of parallel multiplier-temporal buffer-parallel accumulator is present for the convolution-based non-cascaded architecture aiming at the real time Discrete Wavelet Transform(DWT) processing. The convolved multiplication of DWT would be reduced upto 1/4 by utilizing the filter coefficients symmetry and the up/down sampling; and it could be dealt with 3-5 times faster computation by LUT-based DA multiplication of multiple filter coefficients parallelized for product terms with an image data. Further, the reutilization of computed product terms could be achieved by storing in the temporal buffer, which yields the saving of computation as well as dynamic power by 50%. The convolved product terms of image data and filter coefficients are realigned and stored in the temporal buffer for the accumulated addition. Then, the buffer management of parallel aligned storage is carried out for the high speed sequential retrieval of parallel accumulations. The convolved computation is pipelined with parallel multiplier-temporal buffer-parallel accumulation in which the parallelization of temporal buffer and accumulator is optimize, with respect to the performance of parallel DA multiplier, to improve the pipelining performance. The proposed architecture is back-end designed with 0.18um library, which verifies the 30fps throughput of SVGA(800$\times$600) images at 90MHz.

• Journal of Distribution Science
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• v.7 no.1
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• pp.55-70
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• 2009

There is under restructuring of whole distribution market in Mokpo recently. Large-Scale Discount Stores such as E-mart, Lotte Mart, Homeplus and Nonghyup Hanaro Mart entered successfully in the distribution environment in Mokpo. However, the small and medium distributors are falling rapidly, and traditional market is depressed. This status gives some positive effects to make one-stop, good price, good quality and great variety of shopping for saving the time and effort through changing the customers' life-style. This change, however, made the traditional market worse that played as the core channel for trading the local special products and an important role for local economic in retailing market. It is a threatening factor for that traditional market to recover the recession. The decline of traditional market and the bankruptcy of small retailing dealers accelerate the stagnation of local economic and commercial power. Therefore, it need a systematic and synthetical study to solve the negative factors for improving life of the local resident. This paper looked into the concept, issues and development strategy of traditional market that affect local economic development directly. It studied the customers' awareness for traditional market that was recently modernized the facilities in Mokpo. Particularly, based on the research material that was published last academic symposium, it looked about the issues and development strategy that could happen in traditional market not the market of a specific region but all over the country. Therefore, the purpose of this paper is that the central and local government and retailers get a help to make the efficient and useful development strategy through analyzing the effects of customers for modernizing the facilities of traditional market.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.595-606
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• 2009

Two tests were introduced for comparing several survival functions with doubly interval-censored data and illustrated with data surveyed by Korean Cancer Prevention Study (Jee et al., 2005). The test which extended Kim et al. (2006)'s test to the doubly interval-censored data has an advantage over Sun (2006)'s test in terms of saving computation time because the proposed test only depends on the size of risk set, and also the proposed test is applicable to continuous failure time data as well as discrete failure time data unlike Sun's test. Comparing male with female groups on the incubation time of diabetes was highly different and the survival of female group was longer than that of male one. Regardless of gender, the difference in survival functions of four age groups was highly significant with p-value of less than 0.001. This trend was more remarkable for female group than for male one. Simulation results showed that the significance level of both tests was well controlled and the proposed test was better than Sun's test in terms of power.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.91-97
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• 2015

Papermakers wish to increase the filler content of printing and writing grades because it allows saving in production cost through fiber replacement and improving the formation, and optical and printing properties of the paper. However, high filler loading in the base paper has negative side effects. It reduces the mechanical properties of paper and induces cracking at the fold after coating process. Fold cracking is one of the most frequent quality complaints for magazines, high quality books, etc. Two approaches were examined as methods to reduce fold cracking. One approach was to use preflocculated fillers, which was expected to reduce the fold cracking because it would decrease the interfiber bonding. The other approach was to use a new coating binder that gives greater binding power and thereby provides an opportunity of reducing the fold cracking of coated paper. When filler preflocculation was employed in producing the base paper, fold cracking becomes more severe than conventional filler loading condition. On the other hand, use of nano sized binder in coating improved the tensile properties of the coating layer and thereby decreased the crack area. It was shown that tensile properties of coating layer played an important role in fold cracking of coating.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.8
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• pp.1309-1321
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• 2008

Military style is not limited to a single period but represents various image communications related to items, synthetic images and different periodical culture backgrounds. The purpose of this study is to define the communicational function of the military style beginning from the 1st world war up to the modern days, and furthermore explain the characteristics and contents of military styles in different periods by studying the nowadays various symbols of the military style in denotative and connotative aspects. The research method is documentary studies through the literature and academic paper, and examined masters' and doctors' thesis, domestic and overseas books and fashion magazines, photographs and materials collected from the internet. As a result, first, the military style is a significant fashion code in understanding modern fashion by serving as a strong communication function representing people’s ritual through various image items called the 'military look'. Second, the meaning of the image communication through military look changed throughout the different periods. During the 1st and 2nd World war the military look supported Fascism by serving as a media representing extreme patriotism and at the same time social images like functionalism, women liberation, regulation and saving. During the cold war period it was used by young progressives like hippies and punks to send an opposing message towards war and commercialism. Since then up to the 80s it was a medium representing the ‘new role of women’, who possess same social rights and power as the men. However in the 90s the military style had to go through a paradigm transition period. Since this period it got affected by the post modernism and designers, consumers alike adopted military style to create unique beauty It can also be said that it began to be used as a pure fashion code representing intertextuality. It was rather expressed as a metonymy than a metaphor and combined with elegance and feminine factor, which contrasts to the original military concept, it now represents totally new hybrids such as difference, dissemination and varieties.

• Journal of Sensor Science and Technology
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• v.10 no.2
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• pp.101-107
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• 2001

A highly selective, sensitive and reliable ozone sensing $In_2O_3$ thin film was fabricated by a sol-gel method. The fabricated film is operated at a relatively lower temperature than ever developed thin films and saved operating power. $In_2O_3$ films deposited by sol-gel technique has been recently attracted because it is an economical and energy saving method and precisely controlled microstructure. Indium alkoxide precursor was synthesized from the reaction between indium hydroxide and butanol. PVA binder was used to improve adhesion of the films. The $In_2O_3$ thin films were obtained by spin coating from 1 to 5 times followed by drying at $100^{\circ}C$ and calcining at $600^{\circ}C$ for 1h. The film thickness was controlled by the number of coating time. The morphology and the thickness of the $In_2O_3$ films were examined by a SEM and XRD. The $In_2O_3$ thin films show a high sensitive to ozone gas at operating temperature of $250^{\circ}C$. The $In_2O_3$ sensor has very good selectivity to $CH_4$, CO, $C_4H_{10}$ and ethanol.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.73-82
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• 2011

The location-based service is emerging again to the public attention. The location recognition environment up-to-now has been studied with its focus only on a person, an object or a moving object. However, this study proposes a location recognition model that serves to recognize and track, in real time, multiple passengers in a moving vehicle. Identifying the locations of passengers can be classified into two classes: one is to use the high price terminal with GPS function, and the other is to use the economic price compact terminal without GPS function. Our model enables the simple compact terminal to provide effective location recognition under the on-boarding situation by transmitting messages through an interface device and sensor networks for a vehicle equipped with GPS. This technology reduces transmission traffic after detecting the condition of a vehicle (being parked or running), because it does not require transmission/receiving of information on the locations of passengers who are confined in a vehicle when the vehicle is running. Also it extends battery life by saving power consumption of the compact terminal. Hence, we carried out experiments to verify its serviceability by materializing the efficient tracking system for passengers with the detection algorithm of a stopping vehicle proposed in this study. Moreover, about 200 experiments using the system designed with this technology proved successful recognition on on-boarding and alighting of passengers with the maximum transmission distance of 12 km. In addition to this, the running recognition tests showed the test with the detection algorithm of a stopping vehicle has reduced transmission traffic by 41.6% compared to the algorithm without our model.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.3
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• pp.51-61
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• 1989

Recently, the growth in the propulsion power and propeller size of typical energy saving ships has resulted in severe damages of the oil-lubricated stern tube bearing. Consequently, a more rational analytical method for the design of the shafting system is required. In this paper an analytical method applicable to the design of the oil-lubricated stern tube bearing and shafting system is presented. The method consists of the finite element analysis of the shafting system and the oil film hydrodynamics. The shafting system is modeled as a three-dimensional problem using beam elements taking account for the steady components of thrust, lateral forces and moments of the propeller as well as the elastic foundation effects. The oil film hydrodynamics is modeled as a two-dimensional problem. Equal and retangular elements employing hourglass control method are used for the construction of the oil film fluidity matrix. To search the quasi-static equilibrium position between the propeller shaft and the oil film, an optimization technique is employed. Some numerical results based on the proposed method are compared with some measured and numerical data available. They show acceptable agreements with the data.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.153-163
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• 2020

Compared to gaeous hydrogen, liquid hydrogen has approximately 1/800 volume, 800 times higher volumetric energy density at the same pressure, and the advantage of lower explosion risk and easier transportation than gaseous hydrogen. However, hydrogen liquefaction requires larger scale facility investment than simple compression storage method. Therefore, the research on energy-saving hydrogen liquefaction processes is highly necessary. In this study, helium/neon (mole ratio 80 : 20) refrigeration cycle was investigated as the main refrigeration process for hydrogen liquefaction. Process simulation for less energy consumption were carried out using PRO/II with PROVISION V10.2 of AVEVA. For hydrogen liquefaction, energy consumption was compared in three cases: Using a helium/neon refrigerant cycle, a SMR+helium/neon refrigerant cycle, and a C3-MR+helium/neon refrigerant cycle. As a result, the total power consumptions of compressors required to liquefy 1 kg of hydrogen are 16.3, 7.03 and 6.64 kWh, respectively. Therefore, it can be deduced that energy usage is greatly reduced in the hydrogen liquefaction process when the pre-cooling is performed using the SMR process or the C3MR process, which have already been commercialized, rather than using only the helium/neon refrigeration cycle for the hydrogen liquefaction process.