• Journal of Communications and Networks
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• v.4 no.4
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• pp.351-362
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• 2002

In this paper, we introduce a new approach to the minimum energy routing (MER) for next generation (NG) multihop wireless networks. We remove the widely used assumption of deterministic, distance-based channel model is removed, and analyze the potentials of MER within the context of the realistic channel model, accounting for shadowing and fading. Rather than adopting the conventional unrealistic assumption of perfect power control in a distributed multihop environment, we propose to exploit inherent spatial diversity of mobile terminals (MT) in NG multihop networks and to combat fading using transmit diversity. We propose the cooperation among MTs, whereby couples of MTs cooperate with each other in order to transmit the signal using two MTs as two transmit antennas. We provide the analytical framework for the performance analysis of this scheme in terms of the feasibility and achievable transmit power reduction. Our simulation result indicate that significant gains can be achieved in terms of the reduction of total transmit power and extension of network lifetime. These gains are in the range of 20-100% for the total transmit power, and 25-90% for the network lifetime, depending on the desired error probability. We show that our analytical results provide excellent match with our simulation results. The messaging load generated by our scheme is moderate, and can be further optimized. Our approach opens the way to a new family of channel-aware routing schemes for multihopNG wireless networks in fading channels. It is particularly suitable for delivering multicast/ geocast services in these networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.10A
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• pp.1177-1188
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• 2004

This paper describes and analyzes the performance of MB-OFDM UWB system that is suggested as one of standards in IEEE 802.15 TG3a for UWB application. UMBchannel model that has been contributed in IEEE 802.15 SG3a is a wideband channel model of 6Ghz bandwidth, so we modify it to have 3 subband channels that are obtained by filtering conventional U Channel, considering center frequency hopping and system bandwidth. From simulations, we compare performances of MB-OFDM system in AWGN and WB channel and verify the frequency and time domain diversity gains from time End frequency spreading technique. We also compare and analyze the performance of proposed SFBC MB-OFDM with that of conventional MB-OFDM system. Simulation results show SFBC MB-OFDM system outperforms conventional MB-OFDM system about 1.5dB of Eb/No at target BER of 10$^{-m4}$./.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.1
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• pp.100-112
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• 2001

The purpose of this study is to construct the evaluation criteria based on the relative importance and various combination of each evaluation index and then to evaluate urban biotope in terms of conservation of species and habitat. After the standard of evaluation had been developed through the literature review, the relative importance of the evaluation index through expert survey was found out, and the evaluation model of biotope value has been established. The results of this study are as follows; 1) We have constructed the nineteen evaluation criteria through literature reviews, and have provided relative importance to each evaluation index of the diversity of typical species in biotope, afforestation rate, stratification, Hemeroby grads, and the diversity of landscape patterns based on the results of expert survey. and then we have constructed the evaluation system using the relative importance criteria. 2) To evluate urban biotope using the evaluation system constructed, we selected 14 sites. The final evaluation results of each site is as follows; The III grade areas are Seohan and Hwasung high-rise apartment at Beummul-Dong, Korea Men Power /Agency in Sungs 대 industrial zone, the adjacent area of St. Tongil, and Hyomyung elementary school. The II grade areas are the farm land behind the third Anshim Jugong apartment, and Ehyun park. The I grade areas are swampy land in front of Kangchon and Anshim construction site, water space with semi-natural style in front of Gangchon Woobang apartment, forest zone near page Temple at mt. Palgong, the edge area of Jisan and Gosan, and the tendril yard against Anshim middle school. The only grade IV area is the commercial zone near Taegu Department 3) It is highly useful to evaluate urban biotope using the evaluation criteria constructed for this research, the evaluation criteria we developed may be difficult to guarantee the ability for reproduction and recovery, the appearance-number of the rare and endangered species are difficult to estimate urban biotopes. In the future, it is highly useful to evaluate biotope in terms of conservation of species and habitat through its valuation criteria developed in this research and it is necessary to develop the evaluation criteria applicable to estimation of biotope inventory and reproduction of biotope.

• The Journal of Information Systems
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• v.29 no.4
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• pp.25-43
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• 2020

Purpose The purpose of this study is to gradually increase the use of O2O services in recent years. It is a part of our daily lives, and accommodation/leisure is a part of the growing use of O2O services. Based on various prior research related to O2O service, the Commission intends to establish the justification and necessity of empirical research and to establish the relationship between O2O service impact factors and practical value, customer satisfaction and reuse intention. Design/methodology/approach This study analyzed what factors affected the intention of re-use of domestic accommodation O2O services. This research model was proposed based on the preceding research paper, and reliability, diversity, economics, leisure, safety and personalization were used as independent variables, practical value and customer satisfaction are parameters, and reuse intent is composed of dependent variables. Within the last year, users of domestic accommodation applications were selected as users who used domestic accommodation applications more than once, and data of domestic accommodation application users were analyzed using the SPSS 25.0 and AMOS 20.0 programs. Findings The results of this study show that economic efficiency, safety and personalization have significant effects on practical values in the relationship between O2O service impact factors and their impact on practical values. On the other hand, reliability, diversity and leisure were found to have no significant impact on practical values. In terms of O2O service impact factors and their impact on customer satisfaction, leisure and safety have significant effects on customer satisfaction. On the other hand, reliability, diversity, economics, and individualization have shown no significant impact on customer satisfaction. Practical values, parameters, customer satisfaction, and re-use intent, which are dependent variables, were also shown to have significant effects on practical values and customer satisfaction in the relationship.

• The Korean Journal of Franchise Management
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• v.14 no.1
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• pp.39-55
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• 2023

Purpose: This study is designed to grasp how consumers' beliefs about the lunch box attributes such as healthiness, diversity, price, hygiene, and package eco-friendliness affect consumers' perceived value and purchasing behavior. Research design, data, and methodology: The data were collected from 615 respondents composed of men and women aged 20 to 59 who purchased lunch box products and were sampled using the quota sampling method. An online survey was conducted. The data were analyzed using the measurement model and structural equation model assessment with SPSS 24 and SmartPLS 4.0. Results: First, healthiness, diversity, hygiene, and the price had a significant positive effect on the perceived functional value of consumers, but package eco-friendliness did not significantly affect functional value. On the other hand, healthiness, diversity, price, and package eco-friendliness were found to have a positive impact on consumers' perceived emotional value, but hygiene was found to have no significant effect on emotional value. It was found that functional and emotional values significantly positively affected repurchase intention. Conclusions: This study confirmed that consumers' belief in the product attributes of franchise lunch boxes influenced consumers' perceived value, which thus formed the attitude of consumers and showed a relationship that affects repurchase intention. At the end of this paper, the managerial implications for the franchise lunch box brand, the limitations of this study, and future research directions were presented.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.101-104
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• 2003

In this paper, we analyze the performance of transmitter and receiver of W-CDMA system using the space-time code in downlink over JTC realistic channel model. We can get a diversity gain by using the space time code. We also apply the RAKE receiver to improve a performance in multi-path fading channel environment.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.109-124
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• 2001

This paper presents a new method that can efficiently solve the integrated problem of line balancing and model sequencing in mixed model assembly lines (MMALs). Line balancing and model sequencing are important for an efficient use of MMALs. The two problems of balancing and sequencing MMALs are tightly related with each other. However, In almost all the existing researches on mixed-model production lines, the two problems have been considered separately. In this research, an endosymbiotic evolutionary a1gorithm, which is a kind of coevolutionary a1gorithm, is adopted as a methodology in order to solve the two problems simultaneously. This paper shows how to apply an endosymbiotic evolutionary a1gorithm to solving the integrated problem. Some evolutionary schemes are used In the a1gorithm to promote population diversity and search efficiency. The proposed a1gorithm is compared with the existing evolutionary algorithms in terms of solution quality and convergence speed. The experimental results confirm the effectiveness of our approach.

• Journal of Korean Institute of Industrial Engineers
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• v.6 no.1
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• pp.17-22
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• 1980

The performance of scientific researchers has been studied from a number of different aspects, mostly in developed countries. This paper attempted to identify salient factors influencing scientific performance at individual level in a developing country. A model describing the productivity and performance of scientific researchers was developed. Four hypotheses were derived from the model; i) the degree of diversity of a researcher will affect the degree of his scientific performance, ii) the degree of dedication will affect the degree of his performance, iii) the degree of research pressure will affect the degree of his performance, and iv) the degree of satisfaction will affect the degree of his performance. Data were collected through questionnaires responded by 48 researchers from two research organizations. The results of data analysis supported the hypotheses in part. Specifically, diversity measured by the number of research areas was related to the productivity of research reports (p<0.05); research pressure influenced the average number of research papers (p<0.05). The results of hypothesis testing of the satisfaction showed mixed directions according to the indicators. Even though the results of data analysis did not support the hypotheses unanimously, probably due to the limitation of sample size, most of the descriptive analysis indicated that the direction of hypotheses in developed countries seemed to be similar in developing country too. However, more research efforts are needed to verify the research findings of developed countries in developing countries.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.442-460
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• 2021

Nowadays, recommendation systems (RSs) are applied to all aspects of online life. In order to overcome the problem that individuals who do not meet the constraints need to be regenerated when the many-objective evolutionary algorithm (MaOEA) solves the hybrid recommendation model, this paper proposes a many-objective particle swarm optimization algorithm based on multiple criteria (MaPSO-MC). A generation-based fitness evaluation strategy with diversity enhancement (GBFE-DE) and ISDE⁺ are coupled to comprehensively evaluate individual performance. At the same time, according to the characteristics of the model, the regional optimization has an impact on the individual update, and a many-objective evolutionary strategy based on bacterial foraging (MaBF) is used to improve the algorithm search speed. Experimental results prove that this algorithm has excellent convergence and diversity, and can produce accurate, diverse, novel and high coverage recommendations when solving recommendation models.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.14-22
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• 2011

In this study, 15 simple sequence repeat (SSR) markers were used to analyze the population structure of 55 mungbean accessions (34 from South Asia, 20 from West Asia, 1 sample from East Asia). A total of 56 alleles were detected, with an average of 3.73 per locus. The mean of major allele frequency, expected heterozygosity and polymorphic information content for 15 SSR loci were 0.72, 0.07 and 0.33 respectively. The mean of major allele frequency was 0.79 for South Asia, and 0.74 for West Asia. The mean of genetic diversity and polymorphic information content were almost similar for South Asian and West Asian accessions (genetic diversity 0.35 and polymorphic information content 0.29). Model-based structure analysis revealed the presence of three clusters based on genetic distance. Accessions were clearly assigned to a single cluster in which >70% of their inferred ancestry was derived from one of the model-based populations. 47 accessions (85.56%) showed membership with the clusters and 8 accessions (14.54%) were categorized as admixture. The results could be used to understanding the genetic structure of mungbean cultivars from these regions and to support effective breeding programs to broaden the genetic basis of mungbean varieties.