• Journal of the Optical Society of Korea
• /
• v.17 no.6
• /
• pp.467-470
• /
• 2013

We propose a blind feedforward phase noise mitigation method in the time-domain for a coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. By exploiting the redundancy of the cyclic prefix (CP), the proposed scheme acquires the overall phase noise difference information during an OFDM block and attempts to mitigate the phase noise in the time domain using a linear approximation. The proposed algorithm mitigates common phase error (CPE) and inter-carrier-interference (ICI) due to phase noise simultaneously, improving the system performance, especially when decision-directed equalizers are used. The simulation results demonstrate the effectiveness of the proposed feedforward phase noise mitigation approach in time domain.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.12 no.1
• /
• pp.258-269
• /
• 2020

This paper proposes Snapping Shrimp Noise (SSN) detection and corrupted Orthogonal Frequency Division Multiplexing (OFDM) reconstruction methods to increase Bit Error Rate (BER) performance when OFDM transmitted signal is corrupted by impulsive SSNs in underwater acoustic communications. The proposed detection method utilizes multilayer wavelet packet decomposition for detecting impulsive and irregularly concentrated and SSN energy in specific frequency bands of SSN, and the proposed reconstruction scheme uses iterative decision directed-subcarrier reconstruction to recover corrupted OFDM signals using multiple carrier characteristics. Computer simulations were executed to show receiver operating characteristics curve for the detection performance and BER for the reconstruction. The practical ocean experiment of SAVEX 15 demonstrated that the proposed method exhibits a better detection performance compared with conventional detection method and improves BER by 250% and 1230% for uncoded and coded data, respectively, compared with the conventional reconstruction scheme.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.19 no.4
• /
• pp.435-446
• /
• 2021

This article examines the consequences of a significant spent fuel management decision or event in the United States, South Korea and Taiwan. For the United States, it is the financial impact of the Department of Energy's inability to take possession of spent fuel from commercial nuclear power companies beginning in 1998 as directed by Congress. For South Korea, it is the potential financial and socioeconomic impact of the successful construction, licensing and operation of a low and intermediate level waste disposal facility on the siting of a spent fuel/high level waste repository. For Taiwan, it is the operational impact of the Kuosheng 1 reactor running out of space in its spent fuel pool. From these, it draws six broad lessons other countries new to, or preparing for, nuclear energy production might take from these experiences. These include conservative planning, treating the back-end of the fuel cycle holistically and building trust through a step-by-step approach to waste disposal.

• International Journal of Computer Science & Network Security
• /
• v.22 no.1
• /
• pp.319-323
• /
• 2022

The information research system continues to be developed and directed at leading research National Institute of Technology (ITN) Malang in accordance with the Research Strategic Plan of ITN Malang. One of them is a computer system in a complete integrated facility management activity, such as this research scheme. The purpose of this research is to combine and integrate people, places, product, processes and technology. All of them are integrate existing organizational factors into a more effective, simplifying of complex processes, identifying and scheduling, notes, decision makers and more. This research was conducted in stages by design with a structured model stage for 3 (three) years (focus on humans, products and processes), research on Integration Facility Management: Interface Coordination in human resources and product management have been completed on 2019 and 2020. While the focus of research this year is to obtain an integrated facility management Interface Coordination in Process Management.

• Journal of KIISE:Software and Applications
• /
• v.36 no.5
• /
• pp.401-410
• /
• 2009

In order to derive hidden information (concept subsumption, concept satisfiability and realization) of OWL ontology, a number of OWL reasoners have been introduced. The most of these ontology reasoners were implemented using the tableau algorithm. However most reasoners simply report this information without providing a justification for any arbitrary entailment and unsatisfiable concept derived from OWL ontologies. The purpose of this paper is to investigate an optimized method for non-deterministic rule of the tableau algorithm and finding axioms to cause inconsistency in ontology. In this paper, therefore, we propose an optimized method for non-deterministic rule and finding axiom to cause inconsistency using NATMS. In the first place, we introduce Dependency Directed Backtracking to deal non-deterministic rule, a tableau-based decision procedure to find unsatisfiable axiom Furthermore we propose an improved method adapting NATMS.

• The Journal of Korean Association of Computer Education
• /
• v.17 no.6
• /
• pp.103-113
• /
• 2014

This study designed and implemented a query model for consecutive analyses of dynamic multivariate graph data. First, the query model consists of two procedures; setting the discriminant function, and determining an alteration method. Second, the query model was implemented as a query system that consists of a query panel, a graph visualization panel, and a property panel. A Node-Link Diagram and the Force-Directed Graph Drawing algorithm were used for the visualization of the graph. The results of the queries are visually presented through the graph visualization panel. Finally, this study used the data of worldwide import & export data of small arms to verify our model. The significance of this research is in the fact that, through the model which is able to conduct consecutive analyses on dynamic graph data, it helps overcome the limitations of previous models which can only perform discrete analysis on dynamic data. This research is expected to contribute to future studies such as online decision making and complex network analysis, that use dynamic graph models.

• Korea Journal of Hospital Management
• /
• v.3 no.1
• /
• pp.219-237
• /
• 1998

Economists have identified informed consumer choice as one element of a better-functioning health care market, and thus increased attention is directed to the role of information in the health care system. In this country, however, little work has been done for understanding consumers' search behavior in health care market. Based upon this observation, expectant mothers' information search for the choice of delivery care institution was investigated. In doing so, two hypotheses were proposed: 1) Those women who were more active in the search for information would make choice of a delivery care institution with more confidence and would feel greater subsequent satisfaction. 2) The activeness of expectant mothers in information search would depend upon their various personal characteristics, such as socio-economic status, obstetric conditions, and knowledge and attitudes in relation to delivery and health care. The data used for the analysis were collected through face-to-face interviews with those women who had childbirth during the period from January 1, 1996 to the date of interview in February 1998. The survey was conducted using prepared structured questionnaire in Seoul. The sample was drawn from each of arbitrarily defined four regions of Seoul, Northeast, Northwest, Southeast and Southwest, in proportion to the number of births reported in 1996 in each of them. The distribution of the interviewed women by educational level was made similar to that of mothers of new babies reported in 1996. The sample size was planned to be about 300, but ended up with 319. The results of analysis were generally consistent with the proposed hypotheses. Apparently, information increased expectant mothers' confidence in selecting a delivery care institution and subsequent satisfaction with the institution. Indication is that policy efforts should be strengthened to produce and disseminate relevant, comprehensible and credible information that can aid patient decision making. Also, attention should be directed to motivate patients to actively engage in information search from adequate sources.

• CELLMED
• /
• v.2 no.1
• /
• pp.8.1-8.4
• /
• 2012

There are few reports about the beliefs of psoriasis patients related to their disorder and therapy modalities except for the medical ones. We aimed to investigate the beliefs of psoriasis patients about their disorders, where they had attended therapies unrelated to dermatologists and what modality of unconventional therapies they used for psoriasis in Turkey. The study was performed on 141 psoriasis patients. The age, sex, education status and the number of visits to the dermatology clinics were recorded. How the patients decided to visit the dermatology clinic (themselves, directed by others), where they attended for treatment of psoriasis outside of the dermatologist, what they think about the causes of their disease and what they used for treatment of psoriasis were asked. The mean age of the patients was $33.44{\pm}15.13$ years. The patients whose ages were over 30 years significantly more went to dermatology clinics. 68.1% of the patients attended the dermatology clinic based on the individual decision, 18.4% were directed by family members and 5.7% by friends. 45.4% of the patients believed that stress was the cause of their disease. 54.6% of the patients had used at least one type of unconventional therapy for psoriasis. The most frequently used unconventional therapy forms were herbal (24.1%) and spiritual therapies (22%). One conclusion is psoriasis patients need education about their diseases. Dermatologists should have information about the tendencies of the patients and approach the patients with sensitivity and empathy and give objective knowledge about psoriasis.

• Journal of The Korean Association of Information Education
• /
• v.7 no.2
• /
• pp.207-217
• /
• 2003

Individual studying that compose knowledge and improve efficiency of studying through collection of information by various class strategy which takes advantage of web, and Cooperative learning that can elevate sense of responsibility and solve the problem through communication with another person have been developed actively. But, individuation tutoring materials that is developed present doesn't fit of causing learner's interest, and stimulating curiosity about problem because mostly studying is gone in presentation form. Also, cooperative learning materials are lacking connection with actual course of education, application is difficult in real class spot. So, this research has applied self-directed learning, centered with interested operation activity, aimed at improvement in various thought. Also, we have developed social studies tuition-learning system, purpose to the management is possible with on-line project studying which could improve mind-decision ability and ICT application ability. This system is developed for flexible management could be possible in various class circumstance, and level learning could be done through accomplishment-test and the result could be applied by feedback process.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.8
• /
• pp.17-22
• /
• 2016

For the self-adaptive equalization of higher-order QAM systems, this paper proposes a new soft decision-directed (SDD) algorithm that opens the eye patterns quickly as well as significantly reducing the error level in the steady-state when it is applied to the initial equalization stage with completely closed eye patterns. The proposed method for M-QAM application minimized the computational complexity of the existing SDD by the symbol estimated based on the two symbols closest to the observation, and greatly simplified the soft decision independently of the QAM order. Furthermore, in the symbol estimating it increased the reliability of the estimates by applying the superior properties of the sigmoid function and avoiding the erroneous estimation of the threshold function. In addition, the initialization performance was improved when an error is generated to update the equalizer, weighting the symbol decision by the threshold function to the error, resulting in an extension of the range of error fluctuations. As a result, the proposed method improves remarkably the computational complexity and the properties of initialization and convergence of the traditional SDD. Through simulations for 64-QAM and 256-QAM under multipath channel conditions with additive noise, the usefulness of the proposed methods was confirmed by comparing the performance of the proposed 2-SDD and two forms of weighted 2-SDD with CMA.