• Journal of Communications and Networks
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• v.18 no.1
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• pp.50-64
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• 2016

Nowadays, smart meter (SM) technology is widely effectively used. In addition, power allocation (PA) and channel selection (CS) are considered problems with many proposed approaches. In this paper, we will suggest a specific scenario for an SM configuration system and show how to solve the optimization problem for transmission between SMs and the data concentrator unit (DCU), the center that collects the data from several SMs, via simulation. An efficient CS with PA scheme is proposed in the TV white space system, which uses the TV band spectrum. On the basic of the optimal configuration requirements, SMs can have a transmission schedule and channel selection to obtain the optimal efficiency of using spectrum resources when transmitting data to the DCU. The optimal goals discussed in this paper are the maximum capacity or maximum channel efficiency and the maximum allowable power of the SMs used to satisfy the quality of service without harm to another wireless system. In addition, minimization of the interference to the digital television system and other SMs is also important and needs to be considered when the solving coexistence scenario. Further, we propose a process that performs an interference analysis scheme by using the spectrum engineering advanced Monte Carlo analysis tool (SEAMCAT), which is an integrated software tool based on a Monte-Carlo simulation method. Briefly, the process is as follows: The optimization process implemented by genetic evolution optimization engines, i.e., a genetic algorithm, will calculate the best configuration for the SM system on the basis of the interference limitation for each SM by SEAMCAT in a specific configuration, which reaches the solution with the best defined optimal goal satisfaction.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.195-203
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• 2018

With the explosion of SNS(social network services) users, the social commerce market has emerged as a new consumer market, and will continue to grow in recent years. Despite the market environment, however, studies are lacking as to the causes of frustration that are hurting social commerce activation. This study is based on the 'Hezbollah' 2 Factor Theory and is a study of social commerce users' satisfaction and frustration factors. For this purpose, social commerce site characteristics and user characteristics were first derived from interviews and literature reviews to confirm their relationship to satisfaction and dissatisfied products. The results showed that the price discount rate, diversity, regional infrastructure, and e-commerce familiarity resulted in the impact on the definition of satisfaction, while the price discount rate, interoperability and innovation resulted in the definition of unsatisfactory goods. It also showed that satisfaction affects the definition of intended use. In particular, the price discount rate was found to be the only factor affecting the definition of unsatisfactory as well as affecting the definition of satisfaction.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.3
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• pp.39-52
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• 2000

The purpose of this paper is to investigate the difference in facilities of natural recreation forests developed by public and private body to answer the research that what is the difference in development of natural recreation forest between public and private developer\ulcorner After reviewing the literatures, developer's decision-making and motivation of investment, and the planning process of natural recreation forest, we had constructed th conceptual framework and have found the hypothesis of this research. Using data on development status of natural recreation forests and questionnaire surveying of 625 visitors from 9 among 72 natural recreation forests in Korea, We analyzed the data through the comparison of quantity of facilities per 1000 visitors and logistic regression method for quality of facilities. We have found that 1) the six facilities have been turned out to be statistically significant in determining the difference of public and private recreation forests. i.e., infrastructure including roads, maintenance and information and lodging and evacuation, indoor education, outdoor education, and shopping, 2) public recreation forests are well equipped such basic facility as roads, maintenance and information, lodging and evacuation while private recreation forests are well equipped such facility as indoor education, outdoor education, and shopping, and 3) the importance of such facility as roads, maintenance and information, lodging and evacuation, outdoor education, and shopping have been turned out to have 1.99, 2.26, 1.99, 3.01 and 2.24 times more important than that of indoor education, respectively. We can conclude that public recreation forest seems to be equipped with the facilities for sound recreational opportunities for general public, and private recreation forest turned out to have more facilities for pursuit of profits, installed basic facilities for user convenience and service, and special facilities for attracting user and raising revenue. Using the results of this research, we can make a guideline for a market positioning, and standards and provisions of natural recreation forests. We suggest that the relationship between user-satisfaction and recreation facility is needed to be examined in the future research.

• Journal of KIISE:Software and Applications
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• v.33 no.11
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• pp.953-964
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• 2006

Due to the usefulness of the collaborative filtering, it has been widely used in both the research and commercial field. However, there are still some challenges for it to be more efficient, especially the scalability problem, the sparsity problem and the cold start problem. In this paper. we address these problems and provide a novel distributed approach based on agents collaboration for the problems. We have tried to solve the scalability problem by making each agent save its users ratings and broadcast them to the users friends so that only friends ratings and his own ratings are kept in an agents local database. To reduce quality degradation of recommendation caused by the lack of rating data, we introduce a method using friends opinions instead of real rating data when they are not available. We also suggest a collaborative filtering algorithm based on user profile to provide new users with recommendation service. Experiments show that our suggested approach is helpful to the new user problem as well as is more scalable than traditional centralized CF filtering systems and alleviate the sparsity problem.

• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.3
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• pp.31-43
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• 2001

In this study, we carried out investigation and analysis on damages in tunnels on order to provide the basic information for the safety assessment of tunnels and to minimize the potential damage of the same kind as investigated. The frequencies of occurrence in terms of 4 items, i.e., service life interval, type of the damage, cause of the damage, and geological condition, were examined and summarized based on 44 foreign and domestic cases of tunnel damages. Also, we carried out a survey research of which the content included 28 questions on the tunnel safety assessment. The answers collected from domestic experts in tunneling suggested that the most probable cause of the tunnel damages was cracking in tunnels at 42~58%. They also suggested that the poor constrution work strongly caused the damages. Therefore, to ensure tunnel safety, high quality of constrution should be maintained as examined. The types of damage and their extent of influence on the overall tunnel safety are of practical importance to be used in the artficial intelligent system for tunnel safety assessment.

• Korea journal of population studies
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• v.8 no.2
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• pp.79-92
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• 1985

Fertility has been declined since 1966 (see Table 1). This fertility reduction was duely caused by age at first marriage, induced abortion and contraceptive practice which has been largely increased in recent years. Although tbe proximate determinant such as induced abortion, age at marriage and breastfeeding can and do have an effect on fertility, the principal cause of the reduction in fertility in Korea during the fertility transition can be supported by correlation between level of fertility and contraceptive prevalence (See Fig. 4). Taking a regression equation between fertility (TER. Y) and prevalence level (X), the total fertility rate in 1984 was estimated as 1.9 and 2.1 based on lenear and expotential function shown as follow; $Y_1$=5.709-0.0549 X and $Y_2$_______80________ 1+e2.433+0.017X ($R^2$=O. 93) ($R^2$=0. 96) Where $Y_1$ and $Y_2$ denote total fertility rates obtained through two equations respectivelly. The peak of contraceptive prevalence was assumdd as 80 percent which is almost upper limit in human society. On the other hand, an observed value of 1984 fertility level obtained from five month period shows 2.1 which is coincident with logistic fitting after the adjustment of response error assumed around 10 to 20 percent, At any rate, fertility of Korean women will have been reached replacement level (2.1) by 1985.Thus policy for family planning program must be reviewed toward the direction of integrated approach particularly with MCH program inasmuch as fertility in Korea has already shown population replacement level that require more good quality of service in family planning and their There must be an advanced level of fertility in Korea because wide use of contraception and induced life abortion and age at marriage will effect modern fertility which shows up and down trend between 2.1 and 1.5 in general.

• Fisheries and Aquatic Sciences
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• v.24 no.10
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• pp.319-329
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• 2021

In the search for antibiotic alternatives from safe and effective medicinal plants against fish pathogenic bacteria, we found that a combined extract (CE) of 1:1 (w/w) ratio of Angelica gigas Nakai roots and aerial parts of Artemisia iwayomogi Kitamura showed antibacterial activity against the fish pathogenic bacteria. By antibacterial activity-guided fractionations and isolations, five compounds were isolated and identified as decursinol angelate (1), decursin (2), xanthotoxin (3), demethylsuberosin (4), and 2,4-dihydroxy-6-methoxyacetophenone (5) through spectroscopic analyses, such as nuclear magnetic resonance (NMR) and mass spectrometry (MS). Among the compounds, 1 and 2 showed the highest antibacterial activities against Streptococcus iniae and Vibrio anguillarum, showing minimum inhibitory concentrations (MICs) of 62.5-250 ㎍/mL. Compounds 3, 4, and 5 were also found to be active, with MICs of 31.25-1,000 ㎍/mL for those strains. Furthermore, active compounds, 1 and 2 in CE were simultaneously quantified using high-performance liquid chromatography-tandem MS (HPLC-MS/MS). The average contents of 1 and 2 in CE was 3.68% and 6.14%, respectively. The established method showed reliable linearity (r² > 0.99), good precision, accuracy, and specificity with intra- and inter-day variations of < 2 % and recoveries of 90.13%-108.57%. These results may be helpful for establishing the chemical profile of CE for its commercialization as an antibiotic alternative in aquaculture.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.131-142
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• 2023

In this paper, we propose a new station selection algorithm to solve the illegal parking problem of shared electric scooters and improve the service quality. Recently, as a solution to the urban transportation problem, shared electric scooters are attracting attention as the first and last mile means between public transportation and final destinations. As a result, the shared electric scooter market grew rapidly, problems caused by electric scooters are becoming serious. Therefore, in this study, text data are collected to understand the nature of the problem, and the problems related to shared scooters are viewed from the perspective of pedestrians and users in 'LDA Topic Modeling', and a station extension algorithm is based on this. Some parking lots have already been installed, but the existing parking lot location is different from the actual area of tow. Therefore, in this study, we propose an algorithm that can install stations at high actual tow density using mixed clustering technology using K-means after primary clustering by DBSCAN, reflecting the 'current state of electric scooter tow in Seoul'.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.3
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• pp.397-417
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• 2022

The purpose of this study was to identify the status of adolescents' user satisfaction with the 22 libraries of Seoul Metropolitan Office of Education and to improve the quality of information services for adolescents by improving the factors of dissatisfaction, and ultimately, to activate the use of young adults in the libraries of the Seoul Metropolitan Office of Education. In addition, in the transition to the digital age, it was attempted to investigate the use of Seoul Metropolitan Office of Education Digital Library in the context of the inevitable change of reading media. Through this, this study suggested planning a reading program that could arouse adolescents' interest and reflect new information technologies, improving the scope and system of e-book services, linking with school libraries, and restructuring library' space.

• Fisheries and Aquatic Sciences
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• v.25 no.12
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• pp.601-618
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• 2022

The genus Semisulcospira is an economically and ecologically valuable freshwater resource. Among the species, Semisulcospira coreana, Semisulcospira forticosta and Semisulcospira tegulata are endemic to the Korean peninsula and Semisulcospira gottschei is widespread in Asia. Therefore, maintenance and conservation of wild populations of these snails are important. We investigated the genetic diversity and population structure of Semisulcospira based on the mitochondrial cytochrome c oxidase subunit I (COI), NADH dehydrogenase subunit 4 (ND4), and combined mitochondrial DNA (COI + ND4) sequences. All four species and various genetic makers showed a high level of haplotype diversity and a low level of nucleotide diversity. In addition, Fu's Fs and Tajima's D neutrality tests were performed to assess the variation in size among populations. Neutrality tests of the four species yielded negative Fu's Fs and Tajima's D values, except for populations with one haplotype. The minimum spanning network indicated a common haplotype for populations of S. coreana, S. tegulata and S. gottschei, whereas S. forticosta had a rare haplotype. Also, genetic differences and gene flows between populations were assessed by analysis of molecular variance and using the pairwise fixation index. Our findings provided insight into the degree of preservation of the species' genetic diversity and could be utilized to enhance the management of endemic species.