• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.6-14
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• 2011

The fast growing of the number of users requires the development of reliable communication systems able to provide higher data rates. In order to meet those requirements, techniques such as Multiple Input Multiple Out (MIMO) and Orthogonal Frequency Division multiplexing (OFDM) have been developed in the recent years. In order to combine the benefits of both techniques, the research activity is currently focused on MIMO-OFDM systems. In addition, for a fast wireless channel environment, the data rate and reliability can be optimized by setting the modulation and coding adaptively according to the channel conditions; and using sub-carrier frequency, and power allocation techniques. Depending on how accurate the feedback-based system obtain the channel state information (CSI) and feed it back to the transmitter without delay, the overall system performance would be poor or optimal. In this paper, we propose a Signal to Noise Ratio (SNR) estimation algorithm where the preamble is known for both sides of the transciever. Through simulations made over several channel environments, we prove that our proposed SNR estimation algorithm is more accurate compared with the traditional SNR estimation. Also, We applied AMC on several channel environments using the parameters of IEEE 802.11n, and compared the Throughput performance when using each of the different SNR Estimation Algorithms. The results obtained in the simulation confirm that the proposed algorithm produces the highest Throughput performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.144-155
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• 2013

This paper presents a low-cost remote power-quality-failure monitoring system (RPMS) using Android App and TI MCU (micro-controller unit), which is appliable to a micro-grid. The designed RPMS testbed consists of smart nodes, a server, and Android APPs. Especially, the C2000-series MCU-based RPMS smart node that is low-cost compared to existing monitoring systems has both a signal processing function for power signal processing and a data transmission function for power-quality monitoring data transmission. The signal processing function implements both a wavelet-based power failure detection algorithm including sag, swell, and interruption, and a FFT-based power failure detection algorithm including harmonics such that reliable and real-time power quality monitoring is guaranteed. The data transmission function implements a low-complexity RPMS transmission protocol and defines a simple data format (msg_Diag) for power monitoring message transmission. We may watch the monitoring data in real time both at a server and Android phone Apps connected to the WiFi network (or WAN). We use RS-232 (or Bluetooth) as the wired (or wireless) communication media between a server and nodes. We program the RPMS power-quality-failure monitoring algorithm using C language in the CCS (Code Composer Studio) 3.3 environment.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.1
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• pp.7-14
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• 2013

Presently, there are many different technologies used for position detection. However, as signal-receiving devices operating in different locations must detect the precise position of objects located at long distances, it is essential to know the precise time at which an object's or a user's terminal device sends a signal. For this purpose, the existing time of arrival (ToA) technology is not sufficiently reliable, and the existing time difference of arrival (TDoA) technology is more suitable. If a TDoA-based electric surveillance system and other tracking devices fail to achieve precise time-synchronization between devices with separation distance operation, it is impossible to obtain correct TDoA values from the signals sent by the signal-receiving devices; this failure to obtain the correct values directly affects the location estimation error. For this reason, the technology for achieving precise time synchronization between signal-receiving devices in separation distance operation, among the technologies previously mentioned, is a core technology for detecting TDoA-based locations. In this paper, the accuracy of the proposed time synchronization and the measurement error in the TDoA-based location detection technology is evaluated. The TDoA-based location measurement error is significantly improved when using the proposed method for time-synchronization error reduction.

• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.29-44
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• 2009

A variety of research efforts, using advanced wireless communication technologies, have been made to develop more reliable traffic information system. This study presents a novel decentralized traffic information system based on vehicle infrastructure integration (VII). A major objective of this study was also to devise a methodology for determining appropriate spacing of roadside equipment (RSE) to fully exploit the benefits of the proposed VII-based traffic information system. Evaluation of travel time estimation accuracy was conducted with various RSE spacings and the market penetration rates of equipped vehicle. A microscopic traffic simulator, VISSIM, was used to obtain individual vehicle travel information for the evaluation. In addition, the ANOVA tests were conducted to draw statistically significant results of simulation analyses in determining the RSE spacing. It is expected that the proposed methodology will be a valuable precursor to implementing capability-enhanced next generation traffic information systems under the forthcoming ubiquitous transportation environment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.367-384
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• 2016

Many countries have developed a safety case suitable to their own countries in order to improve the confidence of disposal safety in deep geological disposal of high-level radioactive waste as well as to develop a disposal program and obtain its license. This study introduces and summarizes the meaning, necessity, and development process of the safety case for radioactive waste disposal. The disposal safety is also discussed in various aspects of the safety case. In addition, the status of safety case development in the foreign countries is briefly introduced for Switzerland, Japan, the United States of America, Sweden, and Finland. The strategy for the safety case development that is being developed by KAERI is also briefly introduced. Based on the safety case, we analyze the efforts necessary to improve confidence in disposal safety for high-level radioactive waste. Considering domestic situations, we propose and discuss some implementing methods for the improvement of disposal safety, such as construction of a reliable information database, understanding of processes related to safety, reduction of uncertainties in safety assessment, communication with stakeholders, and ensuring justice and transparency. This study will contribute to the understanding of the safety case for deep geological disposal and to improving confidence in disposal safety through the development of the safety case in Korea for the disposal of high-level radioactive waste.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.249-261
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• 2014

This study was performed in order to grasp the trends of elementary school children and their parents on their purchasing behavior of processed foods, awareness of food additives and its education experience by analyzing the safety assessment reports of food additives in 2008~2013. The most important factor in purchasing processed foods was safety in both groups followed by nutrition in parents and taste in children, respectively. While purchasing foods, the first item that is checked has been shifted from food additives to the origin of the products. Parents still perceived food additives as the most hazardous factor for food safety; however, recently, children began to regard microbial contaminants as being most hazardous, which is regarded as a desirable educational effect. The most concerned food additives were preservatives, synthetic seasoning and colorants in both groups. However, the awareness level on food additives still remained low as 3.0~3.1/5.0 for parents and 2.4~2.9/5.0 for children. Educational experience on food additives increased in children from 12% in 2008 to 25% in 2013; however, it decreased in parents from 23% in 2008 to 15% in 2013. Information needs for food additives by education and promotion were very high both in parents (4.2~4.5) and children (3.8~4.1). Both groups had an interest in the safety, legal standards of food additives, and foods with food additives, in order. The most reliable resource institutions on food additives were university/research institute and hospital for parents, but, hospital and government for children. The preferred media on food additives were TV and the internet for parents, and school newsletter and TV for children. Overall, the above results demonstrated that the perceptions on food additives did not change much with parents during the last 6 years; however, children's perceptions began to show improvement with the increase of educational experience. Hence, the government needs to make efforts to increase the trust level of consumers by developing educational tools and providing educational experiences including mass media for the promotion of risk communication on food additives.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.19-30
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• 2003

Based upon XML, a standard document format on the web, there have been many active studies on e-Commerce, wireless communication, multimedia technology and so forth. JML is an XML application suitable for understanding and reusing the source code written using JAVA for various purposes. And it is a DTD which can effectively express various information related to hierarchical class structures, class/method relationships and so on. This paper describes a tool which generates JML document by extracting a comment information from Java source code and information helpful for reusing and understanding by JML in terms of the reverse engineering and a tool which generates a skeleton code of Java application program from the document information included in the automatically or manually generated JML document in terms of the forward engineering. By using the result of this study, the information useful and necessary for understanding, analyzing or maintaining the source code can be easily acquired and the document of XML format makes it easy for developers and team members to share and to modify the information among them. And also, the Java skeleton coed generated form JML documents is a reliable robust code, which helps for developing a complete source code and reduces the cost and time of a project.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.9 no.2
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• pp.190-200
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• 2002

Purpose; The purpose of this study was to develop an instrument to measure sexual satisfaction in Korean adults. Method: Development of items for the instrument was done by a collecting, reorganizing, reducing and selecting process based on the literature. A total of 19 items were selected in this process. For evaluation of the appropriateness of the 19 items, questionnaires were given to an expert group consisting of 18 professionals (7 men and 11 women). Eighteen items having a response of 70% in 'very good' item or 'good' item were included as items for the instrument. With these 18 items, a 5 point Likert scale was developed, and reliability and validity tests of the scale were done. The subjects for the test were 1,127 Korean adults living in 11 areas in Korea, Data were collected from Dec. 1, 2000 to Feb. 28, 2001 and analyzed with SPSS/PC+ 10.0 program. Item analysis and factor analysis were used to assess the reliability and validity of the scale. Chronbach alpha and corrected item-total correlation were obtained to verify internal consistency, and principal component analysis with the varimax rotation was used to identify structure validity of the developed tool. Result: Reliability of the scale was .9503 and corrected item-total correlations of the items were distributed from .5208 to 7899. As a result of the factor analysis, the items were categorized into three factors. The cumulative variance of the three factors was 67.1%, and all of the variances of the factors were above 5%. Because factor 1 (8 items) indicated a special feeling of psychological satisfaction with sexual activity, it was named 'psychological factor'. Factor 2 (8 items) indicated a feeling of satisfaction in the interaction with sexual partner through communication and variation, therefore it was named 'interactional factor'. Factor 3 (2 items) was about the frequency and duration of sexual intercourse and indicated physical dimensions of satisfaction, so it was named 'physical factor'. The average score for sexual satisfaction of the 1,127 subjects was 65.32 (${\pm}12.71$), and histogram of the score showed a normal distribution with skewness - .425. Conclusion: Finally, a Korean Sexual Satisfaction Scale(KSSS) was accepted as a 5 point Likert scale with 18 items after the statistical test for reliability and validity. In conclusion, KSSS is a useful instrument which is valid and reliable can be used to understand the sexuality of Korean adults.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.10
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• pp.14-27
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• 2009

Polar Code was proposed by Turkish professor Erdal Arikan in 2006 as an idea that splitted input channel is increasing the cutoff rate. The channel polarization consisted of code sequences with symmetric high rate capacity in a given B-DMC(Binary-input Discrete Memoryless Channel) W. The symmetric capacity is the highest rate achievable subject to using the input letters of the channel with equal probability. The channel polarization is said to a set of given N independent outputs of B-DMC W. In other word, N increases when N is a set of binary-input channels {$W^{(i)}_N\;:\;1{\leq}\;i\;{\leq}\;N$}, in I{WN(i)} as the fraction of indices is near to 1, which is approaching to I(W), and it is near to 0, then to 1-I(W), where I(W) presents high rates in reliable wireless communication channel as inputs of W with equal frequences. After all, {WN(i)} is shown to be a state of channel coding. On the based on this Polar codes, this paper analyzes Polar coding and decoding of Arikan and propose Radix4 Polar coding newly.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.10
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• pp.427-436
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• 2013

In this paper, a method of moving path control of an automatic guided vehicle in an indoor environment through recognition of marker images using vision sensors is presented. The existing AGV moving control system using infrared-ray sensors and landmarks have faced at two critical problems. Since there are many windows in a crematorium, they are going to let in too much sunlight in the main hall which is the moving area of AGVs. Sunlight affects the correct recognition of landmarks due to refraction and/or reflection of sunlight. The second one is that a crematorium has a narrow indoor environment compared to typical industrial fields. Particularly when an AVG changes its direction to enter the designated furnace the information provided by guided sensors cannot be utilized to estimate its location because the rotating space is too narrow to get them. To resolve the occurrences of such circumstances that cannot access sensing data in a WSN environment, a relative distance from marker to an AGV will be used as fingerprinting used for location estimation. Compared to the existing fingerprinting method which uses RSS, our proposed method may result in a higher reliable estimation of location. Our experimental results show that the proposed method proves the correctness and applicability. In addition, our proposed approach will be applied to the AGV system in the crematorium so that it can transport a dead body safely from the loading place to its rightful destination.