• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.491-498
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• 2012

Recently, many papers have been proposed in order to improve the OFDM system performance in T-DMB DOCR (Digital On Channel Repeater), by using removing the feedback signal so that the transmitter power can be increased or by using the equalizer to remove ICI. Despite these efforts, however, signal quality at the receiving terminal has not been improved because of constellation smearing in T-DMB DOCR. In this paper, in order to suppress constellation smearing, we propose an effective equalizer algorithm that can improve system performance. We perform adaptive channel estimation and non-coherent decision directed noise cancellation method that can estimate the channel subsequently during data symbols period in the frequency domain. So we can obtain better quality of the signal at the receiving terminal. In order to secure QoS(Quality of Service) required in T-DMB handsets, we evaluate SNR and BER in T-DMB DOCR(Digital On Channel Repeater) and verified by simulation. In this simulation results, this system is satisfied the performance of BER=$10^{-5}$ at less than SNR=14 dB at the receiver after compensation of phase noise -18 dBc.

• Journal of Korea Port Economic Association
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• v.35 no.3
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• pp.1-18
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• 2019

The competition between port authorities (PAs) and terminal operating companies (TOCs) in providing port logistics services has gained importance. The PAs enter into leasing contracts with TOCs in various ways. This study aims to model a contract method that maximizes the joint profit between a PA and a TOC. Particularly, this study aims to model the equilibrium by comparing four types of contract schemes in the non-coordination, cooperation, Cournot, and collusion models. The results of the analysis show that the two-part tariff scheme generates a higher joint profit than the fixed and fee contracts. It is understood that risk- and profit-sharing between the PAs and TOCs helps the latter to maximize the throughput and the joint profit. These results are expected to provide an important theoretical basis for decision-making about port rent and freight between the PAs and TOCs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4492-4497
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• 2013

An important features of next-generation wireless networks will be heterogeneous environment in which a mobile terminal will be able to connect to multiple radio access networks and network selection mechanisms play an important role in ensuring QoS for users in this environment. In this paper, our study is concerned with an extension of the well known AHP to the group decision making methods. The users requested specific QoS divide into a group and the access networks with similar characteristics split into a group. Between each group, the one group is selected and within that group, the best access networks will be assigned according to priority order by network selection algorithm. The experimental results of MATLAB simulation show that the every user in each services can select the same network with decision value as large as 0.9. Consequently, the proposed network selection mechanism is more effective than conventional one in integrated UMTS and WLAN networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.300-310
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• 2018

The purpose of this study is to compare the change of Well-Dying awareness and decision of university student before and after taking the course of death study. A questionnaire survey was conducted for university students 93 before education, 117 after education who participated in the Death Studies related lectures at Daejeon Metropolitan City for 15 weeks from August to December 2016. The general characteristics of survey are gender, age. grade, major, marriage condition, religion, family member living together and health status. Four items on the perception aspect of death, five items on the aspect of acceptance of death, seven items of death decision and twelve items for death education's interest and importance were configured as a reference scale. The statistical method carried out the chi-square test, the independent sample t-test, and the decision tree analysis. Based on the decision tree, At the time of preparation for death(cancer patient, terminal patient, etc.) and the elderly(65 years old or older), the education transition rate was 66.7%. But After education, 65.3% of the respondents were in adult, middle and high school, under elementary school, university, and graduate school, which showed a significant difference. Therefore we are looking for death education's effectiveness and setting directions for education's period and contents. the negative viewpoints and worries about the implementation of death education at elementary, middle and high schools and universities are resolved and the death education will positively affect the change of attitude of students.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.23 no.2
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• pp.172-183
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• 2016

Purpose: The purpose of this study was to explore the subjective experience of life-sustaining treatment care among nurses in intensive care units. Method: A phenomenology was used for the study. Data were collected from October to December, 2015 using open-ended questions during in-depth interviews. Participants were nurses working in intensive care units and were contacted through purposive techniques. Eight nurses participated in this study. Results: Four categories emerged from the analysis using Colaizzi's method: (a) difficulties due to life-sustaining treatment care, (b) dilemma of extension or cessation of life-sustaining treatment, (c) repressed feelings and emotional exhaustion, and (d) forming values for life-sustaining treatment from nursing experience. Conclusion: Provision of clearer guidelines on life-sustaining treatment which reflect a family-oriented culture is important for nurses in ICU and will promote nurses involvement in the decision-making process of life-sustaining treatment of patients.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.283-285
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• 2005

This paper presents a new two-terminal numerical algorithm for fault location estimation and for faults recognition using the synchronized phasor in time-domain. The proposed algorithm is also based on the synchronized voltage and current phasor measured from the PMUs(Phasor Measurement Units) installed at both ends of the transmission lines. Also the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. In this paper the algorithm is given and estimated using DFT(Discrete Fourier Transform) and the LES(Least Error Squares Method). The algorithm uses a very short data window and enables fast fault detection and classification for real-time transmission line protection. To test the validity of the proposed algorithm, the Electro-Magnetic Transient Program(EMTP/ATP) and MATLAB is used.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.351-356
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• 2004

This study aims to implement an empirical research about the efficiency of container Ports, and to suggest an effective strategy which can operate container Ports more well. This paper presents a new approach to the measurement of efficiency. Data envelopment analysis(DEA), as it is called, has particular applicability in the service sector. This study applies DEA to provide an efficiency measurement for fifty three container ports including Pusan Port. As a result, we suggest several ideas that can improve the efficiency of container terminals. They are as follows. Firstly, we discriminate between efficient and inefficient container ports and then present a method that can move to efficiency container terminal and a benchmarking port. Secondly, we evaluate the efficiency of Pusan port, and grasp the position at the present time, suggest an advanced direction in future.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.383-384
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• 2022

Following the development of technologies such as digital twin, IoT, and AI after the 4th industrial revolution, decision-making problems are being solved based on high-dimensional data analysis. This has recently been applied to the port logistics sector, and a number of studies on big data analysis, deep learning predictions, and simulations have been conducted on container terminals to improve port productivity. These high-dimensional data analysis techniques generally require a large number of data. However, the global port environment has changed due to the COVID-19 pandemic in 2020. It is not appropriate to apply data before the COVID-19 outbreak to the current port environment, and the data after the outbreak was not sufficiently collected to apply it to data analysis such as deep learning. Therefore, this study intends to present a port data augmentation method for data analysis as one of these problem-solving methods. To this end, we generate the container stowage situation of the yard through a generative adversarial neural network model in terms of container terminal operation, and verify similarity through statistical distribution verification between real and augmented data.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.7-19
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• 2012

In this study of estimating the benefits of environmental materials, the CVM method used in environmental economics was applied to estimate the value of pedestrian environment improvement. After finding the Willingness To Pay (WTP) level of residents through CVM, this study attempts to calculate quantitative benefits from the pedestrian environment improvement. In this study, a survey targeting the inhabitants in Seongbuk-gu adjacent to a business area was carried out for pedestrian environment improvement considering form of payment, willingness to pay and such by establishing and showing several virtual scenarios depicting a quiet and comfortable pedestrian environment. As a result, the willingness to pay level of the Seongbuk-gu residents was 627 won of surcharge for pedestrian environment improvement per month. Additionally, the annual total benefits by pedestrian environment improvement was estimated within a range from 1,247,516,820 won to 286,305,110 won.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.217-228
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• 2021

After the integrated fare system has been applied, public transportation and transfer traffic increased. As a result, transfer passengers must be considered in the operation of the bus. Although previous studies have limitations due to utilizing deterministic mathematical models, which fails to reflect the stochastic movements of passengers and buses, in this study, a more realistic bus stop micro-simulation model is proposed. Based on the proposed simulation model, we represent the relationship between bus arrival interval and passenger wait time as a regression model and empirically show the differences between the cases with and without transfer passengers. Also, we propose a method converting passenger waiting time to cost and find optimal bus arrival interval based on the converted cost. It is expected the proposed method enables bottom-up decision making reflecting practical situation.