• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.471-478
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• 2003

Traditionally,, analysis, simulation and measurement have all been used to evaluate the performance of network protocols and functional entities that support mobile wireless service. Simulation methods are useful for testing the complex systems which have the very complicate interactions between components. To develop a mobile call simulator which is used to examine, validate, and predict the performance of mobile wireless call procedures must have the teletraffic model, which is to describe the mobile communication environments. Mobile teletraffic model is consists of 2 sub-models, traffic source and network traffic model. In this paper, we analyzed the network traffic data which are gathered from selected Base Stations (BSs) to define the mobile teletraffic model. We defined 4 types of cell location-Residential, Commercial, Industrial, and Afforest zone. We selected some Base Stations (BSs) which are represented cell location types in Seoul city, and gathered real data from them And then, we present the call rate per hour, cail distribution pattern per day, busy hours, loose hours, the maximum number of call, and the minimum number of calls based on defined cell location types. Those parameters are very important to test the mobile communication system´s performance and reliability and are very useful for defining the mobile network traffic model or for working the existed mobile simulation programs as input parameters.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.921-932
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• 2015

This study analyzed military personnel survivability in regards to offensive operations according to the scientific military training data of a reinforced infantry battalion. Scientific battle training was conducted at the Korea Combat Training Center (KCTC) training facility and utilized scientific military training equipment that included MILES and the main exercise control system. The training audience freely engaged an OPFOR who is an expert at tactics and weapon systems. It provides a statistical analysis of data in regards to state-of-the-art military training because the scientific battle training system saves and utilizes all training zone data for analysis and after action review as well as offers training control during the training period. The methodologies used the Cox PH modeling (which does not require parametric distribution assumptions) and decision tree modeling for survival data such as CART, GUIDE, and CTREE for richer and easier interpretation. The variables that violate the PH assumption were stratified and analyzed. Since the Cox PH model result was not easy to interpret the period of service, additional interpretation was attempted through univariate local regression. CART, GUIDE, and CTREE formed different tree models which allow for various interpretations.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.1
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• pp.31-41
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• 2021

This study targets the city of Paju, Gyeonggi-do, where many challenges are facing ecological assets management due to the increase in recent development. Using the survey data provided by the National Institute of Ecology in Korea, the study analysed the differences in the local residents' perception of local ecological assets. The Q methodology, which is useful for revealing differences in opinions, was applied to classify the narrative groups, which had different points of view in evaluating each asset. Next, the study compared the differences in perceptions of the vulnerability of ecological assets. As a result of the analysis, the city of Paju was divided into two main narrative groups: a 'Nature Conservation Group' and a 'Heritage Conservation Group'. The Nature Conservation Group wanted to prioritize ecologically valuable assets, such as wetlands, brackish zones, and forests. The Heritage Conservation Group preferred preserving ecological assets having a cultural contexts, such as royal tombs, graves, and the surrounding landscape. Evaluating the ecological assets, the two groups identified 23 ecological sites under threat from development among the 25 ecological sites considered. The Nature Conservation Group noted the importance of sites such as the Sannam Wetlands, Gongneungcheon, Gongneungcheon Brackish Zone, and Simhak Mountain. These were considered to be the most vulnerable ecological assets in the city. The study found differences in the perceived values for each ecological asset by residents. The results can serve as useful data for decision-making on ecological asset management in the city of Paju.

• Korean Journal of Materials Research
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• v.32 no.4
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• pp.200-209
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• 2022

In this study, defects generated in the YSZ coating layer of the IN738LC turbine blade are investigated using an optical microscope and SEM/EDS. The blade YSZ coating layer is composed of a Y-Zr component top coat layer and a Co component bond coat layer. A large amount of Cr/Ni component that diffused from the base is also measured in the bond coat. The blade hot corrosion is concentrated on the surface of the concave part, accompanied by separation of the coating layer due to the concentration of combustion gas collisions here. In the top coating layer of the blade, cracks occur in the vertical and horizontal directions, along with pits in the top coating layer. Combustion gas components such as Na and S are contained inside the pits and cracks, so it is considered that the pits/cracks are caused by the corrosion of the combustion gases. Also, a thermally grown oxide (TGO) layer of several ㎛ thick composed of Al oxide is observed between the top coat and the bond coat, and a similar inner TGO with a thickness of several ㎛ is also observed between the bond coat and the matrix. A PFZ (precipitate free zone) deficient in γ' (Ni₃Al) forms as a band around the TGO, in which the Al component is integrated. Although TGO can resist high temperature corrosion of the top coat, it should also be considered that if its shape is irregular and contains pore defects, it may degrade the blade high temperature creep properties. Compositional and microstructural analysis results for high-temperature corrosion and TGO defects in the blade coating layer used at high temperatures are expected to be applied to sound YSZ coating and blade design technology.

• The Journal of Bigdata
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• v.8 no.1
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• pp.83-97
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• 2023

Project evaluation is the process of evaluating the progress and results of a project. Smart city projects can be divided into system components (infrastructure, services, platforms), or projects can run simultaneously for multiple services. In addition, services are developed and expanded through additional projects. In order to ensure that the smart city, which is composed of various projects, proceeds in accordance with the goals and strategies, periodic project evaluation is required during the project implementation process. The smart city project evaluation system proposed in this paper is designed to provide comprehensive and objective indicators by reflecting various factors that must be considered for projects occurring in all stages of planning, design, construction, and operation of smart cities. The indicators derived from the evaluation system can be used by decision makers to determine the direction of smart city project development. In addition, it is designed so that the performance of the project can be evaluated interim before the end of the project and the feedback obtained from it can be reflected. To introduce the application method of the smart city project evaluation system proposed in this study, the evaluation system developed in this study was applied to the smart city project case of Incheon Free Economic Zone (IFEZ). Based on the evaluation results, items that can maximize the improvement effect of each smart city project item were presented, and the direction of smart city project implementation was suggested. By utilizing a smart city project evaluation system that reflects the characteristics of smart city projects that are composed of multiple projects, comprehensive planning and management of smart city projects will be possible, and this study will serve as a reference for identifying priority improvement factors for projects.

• Korean Circulation Journal
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• v.54 no.8
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• pp.454-465
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• 2024

Background and Objectives: The popliteal artery is generally regarded as a "no-stent zone." Limited data are available on the outcomes of drug-coated balloons (DCBs) for popliteal artery disease. This study aimed to evaluate the 12-month clinical outcomes among patients who received DCB treatment for atherosclerotic popliteal artery disease. Methods: This prospective, multicenter registry study enrolled 100 patients from 7 Korean endovascular centers who underwent endovascular therapy using IN.PACT DCB (Medtronic) for symptomatic atherosclerotic popliteal artery disease. The primary endpoint was 12-month clinical primary patency and the secondary endpoint was clinically driven target lesion revascularization (TLR)-free rate. Results: The mean age of the study cohort was 65.7±10.8 years, and 77% of enrolled patients were men. The mean lesion length was 93.7±53.7 mm, and total occlusions were present in 45% of patients. Technical success was achieved in all patients. Combined atherectomy was performed in 17% and provisional stenting was required in 11%. Out of the enrolled patients, 91 patients completed the 12-month follow-up. Clinical primary patency and TLR-free survival rates at 12 months were 76.0% and 87.2%, respectively. A multivariate Cox regression analysis identified female and longer lesion length as the significant independent predictors of loss of patency. Conclusions: DCB treatment yielded favorable 12-month clinical primary patency and TLR-free survival outcomes in patients with popliteal artery disease.

• Journal of the Korean Society of Radiology
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• v.18 no.5
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• pp.473-481
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• 2024

As a result of measuring and evaluating 24 units of 10 types of medical ultrasonic equipment in Gwangju using the multipurpose ultrasonic phantom (ATS-539), all 24 units were 100% passed in the non-inspection area, vertical distance measurement, horizontal distance measurement, axial/side resolution, gray tone and dynamic range items. As a result of analyzing the ultrasonic phantom pass rate according to the number of years of use of ultrasonic equipment in Gwangju, this study derived that the service life of ultrasonic equipment is related to the equipment performance. As the coverage for ultrasonic inspection is gradually expanded starting with the upper abdominal ultrasound, it is time to further manage the quality of ultrasonic inspection. Therefore, in addition to the standard guidelines for performance measurement for abdominal inspection, research on equipment phantom measurement methods and standards that can be used in various ultrasonic inspection areas such as the neck and chest, which have recently become increasingly important in clinical practice, should be conducted at the same time. In addition, quality control standards should be legally established to maintain the optimal performance of ultrasonic imaging devices and to secure the appropriateness of images. In addition, ultrasound imaging devices should be classified as special medical equipment, and it is considered that the level of equipment should be consistently maintained through continuous management so that images beneficial to treatment can be obtained.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.7-18
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• 2012

This study suggested a method of forecasting market-share of each mode after introducing new urban rail transit lines. The study reflected the observed market share of presently operating urban rail transit into forecasting process in order to improve accuracy in predicting market share of each modes. For more realistic representation of the forecasting model, we categorized O/D pairs according to attributes of trip distance, access time and number of transfers. The analysis results of traveler's mode choice behavior with observed data showed that the trip distances are longer, the share of urban rail tends to be higher, and that the number of transfers is fewer and the access times are lesser, the share of urban rail also tends to be higher. Then, incremental logit model was used in estimating mode choice probabilities for O/D pairs along with rail transit lines while utilizing observed market shares of each modes and differences in transit service level. As the next step, the market share of rail transit after introducing new rail transit lines was forecasted by using incremental logit model with the intial share values calculated the previous analysis step. It also reflected changes in level of service for automobile in highway due to changes in highway systems and changes in mode shares after introducing new lines of rail transit. It can be expected that the proposed method would more realistically duplicates phenomena of mode choice behavior for rail transit and that it would be more theoretically logical than the typical existing methods using SP data and incremental logit model or using addictive logit model in this country.

• Korean Security Journal
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• no.7
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• pp.95-124
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• 2004

It can be said that 'the September 11th Terrorist Attacks' in 2001 were not only the indiscriminate attacks on innocent people but also the whole - political, economical and military - attacks on human life. Also, 'the September 11th Terrorist Attacks' can be regarded as the significant events in the history of world, which were on the peak of the super-terrorism or new-terrorism that had emerged from the 1980s. However, if one would have analysed the developments of terrorism from the 1970s, they could have been foreknown without difficulty. The finding from this study can be summarized as the followings, First, in spite that the USA responsive system against terrorism had been assessed as perfect before 'the September 11th Terrorist Attacks', the fragilities were found in the aspects of the response on the new-terrorism or super-terrorism. The previous responsive system before 'the September 11th Terrorist Attacks' had the following defects as the followings: (1) it was impossible to establish the integrated strategy, because the organizations related to the response against terrorism had not integrated; (2) there were some weakness to collect and diffuse the informations related to terrorism; (3) the security system for the domestic airline service in USA and the responsive system of air defense against terrors on aircraft were very fragile. For these reasons, USA government established the 'Department of Homeland Security' of which the President is the head so that the many organizations related to terrorism were integrated into a single management system. And, it legislated a new act to protect security from terrors, which legalized of the wiretapping in spite of the risk of encroachment upon personal rights, increased the jail terms upon terrorists, froze the bank related to terrorist organization, and could censor e-mails. Second, it seem that Korean responsive system against terrors more fragile than that of USA. One of the reasons is that people have some perception that Korea is a safe zone from terrors, because there were little attacks from international terrorists in Korea. This can be found from the fact that the legal arrangement against terrorism is only the President's instruction No. 47. Under this responsive system against terrorism dependent on only the President's instruction, it is expected that there would be a poor response against terrors due to the lack of unified and integrated responsive agency as like the case of USA before 'the September 11th Terrorist Attacks'. And, where there is no legal countermeasure, it is impossible to expect the binding force on the outside of administrative agencies and the performances to prevent and hinder the terrorist actions can not but be limited. That is to say, the current responsive system can not counteract effectively against the new-terrorism and super-terrorism. Third, although there were some changes in Korean government's policies against terrorism. there still are problems. One of the most important problems is that the new responsive system against terrorism in Korea, different from that of USA, is not a permanent agency but a meeting body that is organized by a commission. This commission is controled by the Prime Minister and the substantial tasks are under the National Intelligence Service. Under this configuration, there can be the lack of strong leadership and control. Additionally, because there is no statute to response against terrorism, it is impossible to prevent and counteract effectively against terrorism. The above summarized suggests that, because the contemporary super-terrorism or new-terrorism makes numerous casualties of unspecified persons and enormous nationwide damages, the thorough prevention against terrorism is the most important challenge, and that the full range of legal and institutional arrangements for the ex post counteraction should be established. In order to do so, it is necessary for the government to make legal and institutional arrangements such as the permanent agency for protection from terrorism in which the related departments cooperates with together and the development of efficient anti-terror programs, and to show its willingness and ability that it can counteract upon any type of domestic and foreign terrorism so that obtain the active supports and confidence from citizens.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1379-1385
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• 2007

In domestic transitional zone design, there is regulation to prevent generation of irregular substructure behaviors that negatively influence in prevention of plasticity settlement on approach section and contact section as well as relieve overall track rigidity by reducing sectional foundation and track stiffness difference, but design guideline that considers dynamic behavior of transitional track in actual service line is very insignificant. Therefore in this study, characteristics of transitional track dynamic behaviors by substructure stiffness are researched and measured dynamic response of transitional track by substructure stiffness in order to prove correlation between substructure and track and calculate elasticity(stiffness) and track load of transitional track by using measurement and formula to provide basic information for developing design guideline considering dynamic behavior of service line transitional track.