• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.697-703
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• 2013

We propose an efficient frequency-time domain resource allocation scheme in multi-carrier (MC) direct-sequence code-division multiple-access (DS/CDMA) communications. We consider, as a power allocation strategy in the frequency domain, transmitting each user's DS waveforms over the user's sub-band with the largest channel gain. We then consider rate adaptation in the time domain, where the data rate is adapted such that a desired transmission quality is maintained. We analyze the achievable average data rate of the proposed scheme with fixed average transmission power, and compare the performance to single carrier DS/CDMA systems with power and rate adaptations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4519-4533
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• 2015

Hypertext Transfer Protocol (HTTP) adaptive streaming has become a new trend in video delivery. An HTTP adaptive streaming client needs to effectively estimate resource availability and demand. However, due to the bitrate of the video encoded in variable bitrate (VBR) mode, a bitrate mismatch problem occurs. With the rising demand for mobile devices, the likelihood of cases where two or more HTTP adaptive streaming clients share the same network bottleneck and competing for available bandwidth will increase. These mismatch and competition issues lead to network congestion, which adversely affects the Quality of Experience (QoE). To solve these problem, we propose a video rate adaptation scheme for the HTTP video streaming to guarantee and optimize the QoE. The proposed scheme estimates the available bandwidth according to the bitrate of each segment and also schedules the segment request time to expedite the response to the bandwidth variation. We used a multi-client simulation to prove that our scheme can effectively cope with drastic changes in the connection throughput and video bitrate.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.38-55
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• 2021

Recently, the use of media has become a daily life due to Covid-19, and education using media has expanded for teenagers. The purpose of this study is to empirically verify how media usage characteristics affect social relationships and school adaptation through the self-efficiency and immersion of teenagers at the youth education site. This study was collected and distributed questionnaires to 250 high school students in Seoul from November 14 to November 21, 2020. The results of the study were derived with a total of 249 questionnaires, excluding one missing questionnaire, and the hypothesis was verified using a Covariance Structure Analysis. Research has shown that, first, the existing, individual, and utility among the characteristics of using youth media have a significant effect on self-efficiency, respectively. Second, only entertainment among the characteristics of youth media use was found to have a significant effect on immersion. Third, immersion has a significant definition effect on school adaptation, and self-efficiency has been shown to have a definition impact on social relationships. Based on this study, we believe that it will be used as a fundamental resource for the development of youth media usage and policy direction in the age of the ever-changing Covid-19.

• International Commerce and Information Review
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• v.12 no.4
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• pp.213-234
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• 2010

This study focused on the determining factors of foreign workers employment in Korean companies. To improve our national enterprise's work outcome, it is necessary to establish a rational employment management policy plan so that the Korea can promote influx of foreign workers who have appropriate job skills and are hard-working and well suited for cultural environment. Accordingly, the companies need to develop the program by considering following. First, the duty of skilled foreign workers for employment is an important determinant factor and thus the targeting for foreign workers is necessary to proceed with pre-paced training. Second, reflecting the cultural characteristics of migrant workers, a cultural adjustment program needs to be developed. In this regard, the national program of screening foreign workers at the government level and the adaptation program needs to be launched suitable for local environment.

• Proceedings of the IEEK Conference
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• summer
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• pp.395-399
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• 2004

We present modality conversion as an effective means for QoS management. We show that modality conversion, in combination with content scaling, would give a wider range of adaptation to support QoS at media level. Here, we consider modality conversion with respect to resource constraint and human factor. To represent modality conversion as well as content scaling, we present the overlapped content value (OCV) model that relates the content value of different modalities with resources. The specification of user preference on modality conversion is divided into qualitative and quantitative levels. The user preference is then integrated into the OCV model so that modality conversion correctly reflects the user's wishes. For the conversion of multiple contents, an optimization problem is formulated and solved by dynamic programming. The experiments show that the proposed approach is efficient to be applied in practice.

• Journal of Engineering Education Research
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• v.17 no.5
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• pp.41-50
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• 2014

The purpose of this study was to examine the organization socialization process of engineering novice for the learning and adaptation. Qualitative case study was performed with 5 participants and the collected qualitative data were analyzed using funnel-like method. The findings showed that the organization socialization process proceed in three steps-anticipatory, encounter, and metarmorphosis. Engineering Novice look at the whole organization socialization proces of organization culture and job maladjustment, and the relationship between internal and external organizations to overcome the difficulties arising from the community through the process of becoming a full participant. Socialization of engineering novice is ultimately the organization to respond to new situations and changes in the learning process takes place in the process, talking about a major resource for human resources. This enables organizations to socialize and harmonious human relationships within the organization so that it can be more important than anything else.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.21-40
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• 2019

This paper presents a comprehensive survey of various artificial intelligence (AI) techniques implemented in cognitive radio engine to improve cognition capability in cognitive radio networks (CRNs). AI enables systems to solve problems by emulating human biological processes such as learning, reasoning, decision making, self-adaptation, self-organization, and self-stability. The use of AI techniques is studied in applications related to the major tasks of cognitive radio including spectrum sensing, spectrum sharing, spectrum mobility, and decision making regarding dynamic spectrum access, resource allocation, parameter adaptation, and optimization problem. The aim is to provide a single source as a survey paper to help researchers better understand the various implementations of AI approaches to different cognitive radio designs, as well as to refer interested readers to the recent AI research works done in CRNs.

• Journal of IKEEE
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• v.25 no.4
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• pp.598-606
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• 2021

In this paper, we presents a new service binding and resource management model for context based services in mobile edge computing (MEC) networks. The proposed control is composed of two layers: MEC service bindng control layer (MCL) and user context control layer (UCL). The MCL manages service binding construction, resource allocation, and service policy construction from a system point of view; and the UCL manages real-time service adaptation using meta-objects. Through simulations, we confirmed that the proposed control offers enhanced throughput and content transfer time when it is compared to the legacy computing and control models. The proposed control model can be employed as a key component for the context based various internet-of-things (IoT) services in MEC environments.

• Food Science and Preservation
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• v.22 no.6
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• pp.908-914
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• 2015

The objectives of this study were to isolate and characterize low temperature adaptation yeast and to obtain suitable yeasts strains for manufacturing Yakju. In this study, we isolated 482 wild yeasts from fermented foods. Out of these, 5 yeast strains were selected based on increased growth at low temperature ($15^{\circ}C$) and high ${\beta}$-glucosidase activity. To screen the aromatic level of isolates, media containing cerulenin and 5,5,5-trifluor-DL-leucine (TFL) were used. Y297 strain demonstrated tolerance against TFL and produced more than 13% alcohol. Y297 strain was identified a Saccharomyces cerevisiae based on the 26S rDNA gene sequences. Maximum cell growth was observed after 19 hr and 38 hr of incubation at $25^{\circ}C$ and $15^{\circ}C$, respectively. The exponential phase was followed by a lengthy stationary phase, at $15^{\circ}C$, when the cells remained high viable. Y297 strain demonstrated tolerance against alcohol (10%), glucose (60%) and salt(NaCl, 8%). ${\beta}$-glucosidase and esterase activity in Y297 were higher than those of controls at $15^{\circ}C$. Overall, these results indicated that using wild yeast strain, isolated from fermented food, affects the chemical characteristics of the brewed Yakju.

• Management & Information Systems Review
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• v.33 no.2
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• pp.135-153
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• 2014

Tendencies such as the increasing spread of market globalization, new technological developments, the reduction of product life cycles and aggressive competition, are generating high levels of environmental changes and uncertainty for organizations of all types. these circumstances require rapid responses through adaptation of organizational attitudes and capabilities, which lead to innovative management approaches and organizational methods. Human resource management researchers have struggled to elaborate the underlying mechanism explaining how human resource systems relate to organizational performance after universalistic perspectives were supported by a majority of studies investigating the positive relationship between human resource management system and firm performance. To fill the void, hypotheses in this study predicted human resource flexibility that would mediate the relationship between human resource management system and firm performance. The research model among the variables in this study was as follows: These theoretical models were tested with a sample of 138 firms in Korea. The analysis of data was undertaken by using AMOS. The Summary of the verification results is follows: Firstly, most of human resource management system and human resource flexibility had positive effects on human resource performance Secondly, most of human resource management system and human resource flexibility had positive effects on firm's financial performance Thirdly, human resource flexibility had mediated the relationship between human resource management system and firm performance The results of the present research may be demonstrated that organizations or managers could achieve a high level of management practices that lead to firm performance by enabling human resource to be flexible through high performance human resource management system.