• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.406-413
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• 2001

The energy dissipation or damage prevention capability of structure can be greatly enhanced by employing hysteretic dampers. According to recent studies by the authors, the ratio of hysteretic damper stiffness to structural story stiffness has been identified as one of the most important parameters for characterizing the performance of this damper In this study the method for determining appropriate properties of hysteretic dampers to satisfy the given performance objectives is developed based on the concept of capacity spectrum method. The comparison with the results from inelastic time history analysis proves that the hysteretic dampers designed from the proposed method restrains the displacement well within the target displacement.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.126-128
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• 2011

AIS가 도입된 이후 선박확인절차에 필요한 VHF교신량 감소, Ship to Ship, Ship to VTS간 안전통신의 기회증대와 RADAR에서 발생하는 Swap(물표바뀜)현상 감소 등 자동으로 선박정보를 수신함으로써 VTS구역의 전체적인 통항이미지를 관제사가 쉽게 그릴 수 있어 보다 안전한 관제업무를 수행하는데 기여하고 있다. 하지만 AIS탑재선박의 증가로 AIS기지국/선박국 통신환경에 따른 채널간섭과 AIS신호의 ERROR(오류) 정보 등이 관제업무를 더욱 위험한 상황으로 만드는 경우들이 발생하고 있다. 따라서 본 논문에서는 관제업무를 수행함에 있어서 경험하였던 AIS ERROR 정보로 인한 위험했던 상황들을 분석하여 다른 관제사가 업무 수행시 합리적인 판단을 내릴 수 있도록 AIS특성 및 개선방안을 제시하고자 한다.

• Smart Structures and Systems
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• v.15 no.3
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• pp.609-625
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• 2015

Management of infrastructure stock is essential in sustainability of society, and its analysis and optimization are studied in the light of control system modeling in this paper. At the first part of the paper, cost of stock management is analyzed based on macroscopic statistics on infrastructure stock and economical growth. Stock management burden relative to economy is observed to become larger at low economic growth periods in developed economies. Then, control system modeling of stock management is introduced and by augmenting maintenance actions as control input, dynamic behavior of stock is simulated and compared with existing time history statistics. Assuming steady state conditions, applicability of the model to cross sectional data is also demonstrated. The proposed model is enhanced so that both preventive and corrective maintenance can be included as system inputs, i.e., feedforward and feedback control inputs. Optimal management strategy to achieve specified deteriorated stock level with minimal cost, expressed in terms of preventive and corrective maintenance actions, is derived based on estimated parameter values for corrosion of steel bridges. Relative cost effectiveness of preventive maintenance is shown when target deteriorated stock level is lower.

• Journal of the Korea Society of Computer and Information
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• v.22 no.11
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• pp.97-104
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• 2017

Location prediction has been successfully utilized to provide high quality of location-based services to customers in many applications. In its usual form, the conventional type of location prediction is to predict future locations based on user's past movement history. However, as location prediction needs are expanded into much complicated cases, it becomes necessary quite frequently to make inference on the locations that target user visited in the past. Typical cases include the identification of locations that infectious disease carriers may have visited before, and crime suspects may have dropped by on a certain day at a specific time-band. Therefore, primary goal of this study is to predict locations that users visited in the past. Information used for this purpose include user's demographic information and movement histories. Data mining classifiers such as Bayesian network, neural network, support vector machine, decision tree were adopted to analyze 6868 contextual dataset and compare classifiers' performance. Results show that general Bayesian network is the most robust classifier.

• Journal of Information Technology Applications and Management
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• v.25 no.2
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• pp.73-90
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• 2018

Despite of increasing studies for product recommendation, the recommendation of product repurchase timing has not yet been studied actively. This study aims to propose deep neural network models usingsimple purchase history data to predict the repurchase timing of each customer and compare performances of the models from the perspective of prediction quality, including expected ROI of promotion, variability of precision and recall, and diversity of target selection for promotion. As an experiment result, a recurrent neural network (RNN) model showed higher promotion ROI and the smaller variability compared to MLP and other models. The proposed model can be used to develop a CRM system that can offer SMS or app-based promotionsto the customer at the right time. This model can also be used to increase sales for product repurchase businesses by balancing the level of ordersas well as inducing repurchases by customers.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.3
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• pp.339-345
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• 2016

This paper is concerned with the numerical simulation result of pressure propagation to the main charge by warhead penetration into concrete targets. In this study, we developed on-line pressure measurement method in the main charge during warhead penetration. Using the on-line pressure measurement method, we successfully recorded the pressure-time history in the main charge during the field penetration test. Then we compared result of numerical simulations with test data and found that the simulation results are in good agreement with the test results. Finally, through the numerical calculations it is concluded that the installation of liner is effective in reducing pressure level produced in the main charge.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.549-552
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• 2008

An eight-month-old, intact female Jindo, weighing 9 kg with a one-day history of acute bloody diarrhea was referred. Plain abdominal radiographic findings included evidence of a soft tissue tubular mass within the dilated colon. In ultrasonographs, a target-like mass was identified with multiple hyperechoic and hypoechoic parallel wall layers. A barium enema showed a large radiolucent filling defect within the colon and a completely occlusive lumen. On the basis of these images, ileocecocolic and colocolic intussusception was diagnosed. Surgical manual reduction, resection and anastomosis were performed. The patient recovered normally without any complications or recurrence.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.673-678
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• 1993

A male sika deer, 3 years old, which had the clinical history of chronic watery diarrhea with severe emaciation for 4 months was submitted and euthanized. On necropsy, there was diffuse mucosal hypertrophy of gastrointestinal tract with thickened intestinal walls and swollen mesenteric lymph nodes. In histologic lesions. diffuse proliferation of epithelioid cells are present in the laminar propria, submucosa muscle layer and subserosa of most gastroinlestinal organs except omasum. These epithelioid cells are also present in the cortex and medulla of meseriteric lymph nodes and in the portal triads of liver. Most these epithelioid cells contain acid-fast positive bacilli using Ziehl-Neelsen staining in the cytoplasm. Based on the clinical signs, gross findings and histological lesions, this deer was diagnosed as paratuberculosis. The wide range of target organs and the severity of the lesions observed in this case is quite different comparing to those of other ruminant.

• Molecules and Cells
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• v.26 no.4
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• pp.344-349
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• 2008

5-Fluorouracil (5-FU), a pyrimidine antagonist, has a long history in cancer treatment. The targeted pyrimidine biosynthesis pathway includes dihydropyrimidine dehydrogenase (DPD), which converts 5-FU to an inactive metabolite, and thymidylate synthase (TS), which is a major target of 5-FU. Using Caenorhabditis elegans as a model system to study the functional and resistance mechanisms of anti-cancer drugs, we examined these two genes in order to determine the extent of molecular conservation between C. elegans and humans. Overexpression of the worm DPD and TS homologs (DPYD-1 and Y110A7A.4, respectively) suppressed germ cell death following 5-FU exposure. In addition, DPYD-1 depletion by RNAi resulted in 5-FU sensitivity, while treatment with Y110A7A.4 RNAi and 5-FU resulted in similar patterns of embryonic death. Thus, the pathway of 5-FU function appears to be highly conserved between C. elegans and humans at the molecular level.

• Earthquakes and Structures
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• v.10 no.3
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• pp.563-588
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• 2016

In this study, solution models are proposed to obtain code-compatible ground motion record sets which can be used for both uni-directional and bi-directional dynamic analyses. Besides scaled, unscaled ground motion record sets are obtained to show the utility and efficiency of the solution models. For scaled ground motion sets the proposed model is based on hybrid HS-Solver which integrates heuristic harmony search (HS) algorithm with the spreadsheet Solver add-in. For unscaled ground motion sets HS based solution model is proposed. Design spectra defined in Eurocode-8 for different soil types are selected as target spectra. The European Strong Motion Database is used to get ground motion record sets. Also, a sensitivity analysis is conducted to evaluate the effect of different HS solution parameters on the solution accuracy. Results show that the proposed solution models can be regarded as efficient ways to develop scaled and unscaled ground motion sets compatible with code-based design spectra.