• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.31-42
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• 2015

The plastic stress distribution method and the strain compatibility method are the two representative methods to calculate the P-M interaction strength of RCFT (rectangular concrete filled tube) columns. The plastic stress distribution method is approximate while the stress compatibility method should approach the exact solution if accurate constitutive relations of the materials involved are used. Recent study by the authors pointed out that, because of lack of accurate constitutive model for the concrete confined by the rectangular steel tube, no strain compatibility method according to the current structural provisions provides a satisfactory prediction of the P-M interaction strength of RCFT columns under various material combinations. An empirical constitutive model which can capture the stress-strain characteristics of the confined concrete of RCFT columns is proposed based on analyzing extensive exisitng test database. The key idea was to define the concrete crushing strain as a function of steel-to-concrete strength ratio and width-to-thickness ratio of steel tube. It was shown that the proposed model leads to more accurate and more consistent prediction of the P-M interaction strength of RCFT columns under general design conditions.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.211-216
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• 2013

In general, smoothing filters regularize functions by reducing differences between adjacent values. The smoothing filters, therefore, can regularize inverse solutions and produce more accurate subsurface structure when we apply it to full waveform inversion. If we apply a smoothing filter with a constant coefficient to subsurface image or velocity model, it will make layer interfaces and fault structures vague because it does not consider any information of geologic structures and variations of velocity. In this study, we develop a selective smoothing regularization technique, which adapts smoothing coefficients according to inversion iteration, to solve the weakness of smoothing regularization with a constant coefficient. First, we determine appropriate frequencies and analyze the corresponding wavenumber coverage. Then, we define effective maximum wavenumber as 99 percentile of wavenumber spectrum in order to choose smoothing coefficients which can effectively limit the wavenumber coverage. By adapting the chosen smoothing coefficients according to the iteration, we can implement multi-scale full waveform inversion while inverting multi-frequency components simultaneously. Through the successful inversion example on a salt model with high-contrast velocity structures, we can note that our method effectively regularizes the inverse solution. We also verify that our scheme is applicable to field data through the numerical example to the synthetic data containing random noise.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.30-35
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• 1996

It is well known that the improved methods of the estimation of the service power margin is necessary to design a optimum ship and to operate economically a ship. Unfortunately, most conventional methods of the predicting of the service power margin are not so accurate that attention should be payed to improve this. From this overview, it is importance with. the effects of waves, as recommended by the 15th and 16th International Towing Tank Conference in 1978 and l981. However the progress of research in this field is very slow mainly since it is taken so long time to take data about hull roughness according to ship ages. For instance, it would be taken 17 or 25 years to measure ideally the data for a ship. Moreover it would be also necessary to take data for many types of ships to lead a general solution. A relationship between roughness and ship age are studied in this paper considering full scale data. A comparison is also made between the effects of hull roughness and of weather at sea for the ship.

• Journal of Digital Convergence
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• v.12 no.6
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• pp.23-34
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• 2014

The objective for this research is to analyze the origin of the outbreak of a policy dilemma in the government's pursuance of policy aimed at tackling internet addiction among teenagers, as well as analyzing responsive strategy. Therefore, within this research and as the model of the dilemma being the analytical frame, the aspect of the dilemma has been analyzed through the transformation of contexts, conditions, policy values, alternatives, policy actors and policy decision makers. The major research results are as follows. First, each and every dilemma of 'transformation of context and condition', 'policy value and alternatives', 'policy actors' and 'policy decision makers' in processes of policy in preventing and resolving adolescent internet addiction, it acted as a decisive cause in forming the general dilemma of the policy. Second, the government's strategy in policy response within the policy dilemma conditions turned out to be a duplication of policy, occurrence of contradictions, typical response strategy and cyclical choices. Given these factors, the following characteristics have shown up as a result. First, as the problems in duplication of policy and contradictions occurred within a single policy, the government responded to this dilemma in a typical way, which brought about an even more serious dilemma. Second, the government put in effort to re-regulate two values (protection of adolescents and promotion of the video game industry), which are included in the response policy of adolescent Internet addiction. As a result, the policy dilemma has weakened with respect to the past. However, it has not solved the fundamental problems. This research, taking the results as a background, strives to provide implications for establishing a self-consistent groundwork, which combines policy values and vision for the government to pursue effective responsive policy on adolescent internet addiction, which is becoming more and more severe in the information society in which we live.

• The Journal of Dong Guk Oriental Medicine
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• v.6 no.2
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• pp.87-98
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• 1998

Renal tissues of ICR mouse were intraperitoneally injeced with Monostroma nitidum extract(ME) after Triton WR-1339(TX) injection were observed to investigate the lipid accumulation suppressive effect of ME. The renal tissues were obtained at hour 24, 48, and 72 after TX injection that were fixed in fromol-calcium solution and were cryocut. The tissue stained by H&E for general morphology, sudan black B for lipid and perchloric acid-naphthoquinone method for cholesterol. The parietal layer of Bowman's capsule is swatted as cuboidal type at hour 48 after TX injection and the lipid blot and cholesterol particle were noticeably increased in glomerulus than control group and these appeared in convoluted tubule, collecting tubule, and Helen's loop. But the parietal layer of Bowman's capsule was shaped as squamous type that was looked like as normal morphology in ME treated group after TX injection and the lipid blot and cholesterol particle were considerably decreased in glomerulus than TX group. As results indicated that the accumulation of lipid including cholesterol caused by TX injection were mitigated in renal tissues by the antihyperlipidermic effect of ME.

• Journal of The Korean Association For Science Education
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• v.34 no.7
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• pp.667-675
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• 2014

It is important to know science terminology when learning science. In terms of linguistic and psychological perspectives, the context of encountering a terminology for the first time is critical. If a student has not learned the terminology properly the first time, it might cause misconceptions or be a barrier in following learning. This study aims to identify how careful science terminology are used in science textbooks, and the relationship of using science terminology between science curriculum and middle school science textbooks in the 2009 National Curriculum. In addition, the educational need, the importance of science learning, proper time for teaching, & difficulty of the terminologies have been surveyed among teachers and students. As results of study show, only 25% of terminologies in science textbooks have appeared in the curriculum, and about 10% have been used in middle school science textbooks prior to science curriculum. The survey results suggested that many of those terminologies could cause problems in teaching and learning situation. The solution for them have been divided into the following: avoiding usage in textbook prior to curriculum, using earlier in textbooks, using earlier in curriculum, and reflecting curriculum precisely in the textbook. In general, the curriculum needs to state performing objectives concretely. And it is needed to examine science terminology advertently when writing textbooks.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.449-462
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• 1996

On the reaction crystallization of lanthanum oxalate effects of operation conditions of impeller speed, concentration and feed rate of reactant, and reaction temperature on the nucleation and growth of crystals were investigated experimentally. In general, at low supersation the analysis of crystallization processes is relatively clear. However, at high wupersaturation, which is usually applied in industrial crystallization, the processes are exhibited in much complication. In this study the lanthanum oxalate was crystallized by the reaction crystallization of high concentration of lanthanum chloride and oxalic acid in single-jet semi batch reactor. Agitation of solution and suspension in the reactor influenced to enhance the reaction process and crystal growth process which gave opposite effect on the crystallization of lanthanum oxalate. In our experiment since increase of impeller speed gave more influence on the reaction process rather than on the crystal growth process, the supersaturation concentration increased with increase of impeller speed, then resulted in decrease of mean crystal size. By the same effect of reactant concentration and feed rate, the decrease of mean crystall size of lanthanum oxalate was observed with increasing the reactant concentration and feed rate. In case of increasing reaction temperature, the mean crystal size increased. The morphology of lanthanum oxalate crystal was not changed within the variation ranges of the operation conditions which were applied in our experiment.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2484-2496
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• 2000

High speed switches have been developing to interconnect a large number of nodes. It is important to analyze the switch performance under various conditions to satisfy the requirements. Queueing analysis, in general, has the intrinsic problem of large state space dimension and complex computation. In fact, The petri net is a graphical and mathematical model. It is suitable for various applications, in particular, manufacturing systems. It can deal with parallelism, concurrence, deadlock avoidance, and asynchronism. Currently it has been applied to the performance of computer networks and protocol verifications. This paper presents a framework for modeling and analyzing ATM switch using stochastic activity networks (SANs). In this paper, we provide the ATM switch model using SANs to extend easily and an approximate analysis method to apply A TM switch models, which significantly reduce the complexity of the model solution. Cell arrival process in output-buffered Queueing A TM switch with finite buffer is modeled as Markov Modulated Poisson Process (MMPP), which is able to accurately represent real traffic and capture the characteristics of bursty traffic. We analyze the performance of the switch in terms of cell-loss ratio (CLR), mean Queue length and mean delay time. We show that the SAN model is very useful in A TM switch model in that the gates have the capability of implementing of scheduling algorithm.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.51-58
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• 2018

The late 20th century saw the industrial period end only to transform into the digital era where people have begun to pay attention to craft because it a field that respects emotion as the essential value, an alternative to overcome the side effect that people have created. Today a new world - where the virtual and the real co-exist through artificial intelligence (AI) - has suddenly approached us and the future of craft is faced with a new situation as it needs to present a new creative solution as a tool that is necessary for human way of life - a tool that has been a necessity throughout history and the evolution of life. As a result for a continued development, craft attempts to establish a new paradigm through current trends represented by our modern society, which is the emergence of creative development through convergence. This study presents creative experiments attempted through the convergence of craft with other heterogeneous tendencies connected to the field. The objective of the study is to enable makers to acquire a more creative way of thinking at the same time as inspiring them and suggesting new creative possibilities in order to develop their work through creative convergence. In Chapter 2, the study investigates on the current status of craft in general, and compares it with what is taking place in Korea; in Chapter 3 the significance of convergence in craft and the process of creating is addressed through case studies. Lastly in Chapter 4, with the basis on analytical case studies, the attribute and the potential of convergence in the field of craft is observed. By analyzing different phenomena presented through attempts to converge in contemporary craft, it has been possible to view the future of the 21st century craft through assessments on what is active and what is as yet hidden potential.

• The Journal of Bigdata
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• v.4 no.2
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• pp.159-173
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• 2019

Last-Mile delivery optimization plays a key role in the urban supply chain operation, which is the most expensive and time-consuming and most complicated part of the whole delivery process. The urban consolidation center (UCC) is regarded as a significant asset for supporting customer demand in the last-mile delivery service. It is the key benefit of UCC to improve the load balance of vehicles and to reduce the total traveling distance by finding the better route with the well-organized multi-leg vehicle journey in the urban area. This paper presents the model using multiple scenario analysis integrated with mathematical optimization techniques using Geographic Information System (GIS). The model aims to find the best solution for the distribution network consisted of DC and UCC, which is applied to the case of Ulaanbaatar Mongolia. The proposed methodology integrates two sub-models, location-allocation model and vehicle routing problem. The multiple scenarios devised by selecting locations of UCC are compared considering the general performance and delivery patterns together. It has been adopted to make better decisions the quantitative metrics such as the economic value of capital cost, operating cost, and balance of using available resources. The result of this research may help the manager or public authorities who should design the distribution network for the last mile delivery service optimization using UCC within the urban area.