• Title/Summary/Keyword: Secondary Use

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Power Allocation and Performance Analysis for the Secondary User under Primary Outage Constraint in Cognitive Relay Network (Cognitive Relay 네트워크에서 일차 사용자의 Outage 제약 조건 하에서의 이차 사용자의 파워 할당 기법 및 성능 분석)

  • Kim, Hyung-Jong;Hong, Dae-Sik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.49 no.8
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    • pp.46-51
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    • 2012
  • In this paper, we investigate the power allocation for cognitive relay networks. Cognitive relay networks offer not only increasing spectral efficiency by spectrum sharing but also extending the coverage through the use of relays. For spectrum sharing, conventional works have assumed that secondary users know perfect channel information between the secondary and primary users. However, this channel information may be outdated at the secondary user because of the time-varying properties or feedback latency from the primary user. This causes the violation for interference constraint, and the secondary user cannot share the spectrum of the primary after all. To overcome this problem, we propose the power allocation scheme for the secondary user under the allowable primary user's outage probability constraint. Since the proposed power allocation scheme does not use the instantaneous channel information, the secondary users have lower feedback burden. In addition, the proposed scheme is also robust to the outdated channel environment.

Development and Evaluation of Smart Secondary Controls Using iPad for People with Hemiplegic Disabilities

  • Song, Jeongheon;Kim, Yongchul
    • Journal of the Ergonomics Society of Korea
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    • v.34 no.2
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    • pp.85-101
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    • 2015
  • Objective: The purpose of this study was to develop and evaluate smart secondary controls using iPad for the drivers with physical disabilities in the driving simulator. Background: The physically disabled drivers face problems in the operation of secondary control devices that accept a control input from a driver for the purpose of operating the subsystems of a motor vehicle. Many of conventional secondary controls consist of small knobs or switches that physically disabled drivers have difficulties in grasping, pulling or twisting. Therefore, their use while driving might increase distraction and workload because of longer operation time. Method: We examined the operation time of conventional and smart secondary controls, such as hazard warning, turn signal, window, windshield wiper, headlights, automatic transmission and horn. The hardware of smart secondary control system was composed of iPad, wireless router, digital input/output module and relay switch. We used the STISim Drive3 software for driving test, customized Labview and Xcode programs for interface control of smart secondary system. Nine subjects were involved in the study for measuring operation time of secondary controls. Results: When the driver was in the stationary condition, the average operation time of smart secondary devices decreased 32.5% in the normal subjects (p <0.01), 47.4% in the subjects with left hemiplegic disabilities (p <0.01) and 38.8% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. When the driver was driving for the test in the simulator, the average operation time of smart secondary devices decreased 36.1% in the normal subjects (p <0.01), 41.7% in the subjects with left hemiplegic disabilities (p <0.01) and 34.1% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. Conclusion: The smart secondary devices using iPad for people with hemiplegic disabilities showed significant reduction of operation time compared with conventional secondary controls. Application: This study can be used to design secondary controls for adaptive vehicles and to improve the quality of life of the people with disabilities.

A Hydration Model for Blended Concrete utilizing Secondary Cementitious Powders (혼화재를 사용한 콘크리트의 수화모델)

  • Noh Jea Myoung;Byun Keun Joo;Song Ha-Won
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.140-143
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    • 2004
  • Heat of hydration of concrete under different curing temperatures can be characterized with knowledge of the thermal activity, the heat rate at the reference temperature, and the total heat of hydration of the mixture. The so-called multi-component hydration model incorporates the effect of following variables: cement chemical composition, cement fineness, secondary cementitious powders, mixture proportions, and concrete properties. However, the model does not consider the use of silica fume as a secondary cementitious powder. Therefore, the model that quantifies the heat of hydration due to the use of silica fume is needed. In this thesis, the effects of silica fume on heat of hydration are evaluated and the influence on the heat of hydration are also quantified to be included in the model, so that the analysis using modified multi-component hydration model for silica fume concrete provides more accurate results than normal concrete.

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A Study on the Secondary Buckling Behavior of Ship Plate (선체판부재의 2차좌굴거동에 관한 연구)

  • 고재용
    • Journal of the Korean Institute of Navigation
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    • v.20 no.1
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    • pp.47-58
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    • 1996
  • The use of high tensile steel plates is increasing in the fabrication of ship and offshore structures. The main portion of ship structure is usually composed of stiffened plates. In these structures, plate buckling is one of the most important design criteria and buckling load may usually be obtained as an eigenvalue solution of the governing equations for the plate. To use the high tensile steel plate effectively, its thickness may become thin so that the occurrence of buckling is inevitable and design allowing plate buckling may be necessary. When the panel elastic buckling is allowed, it is necessary to get precise understandings about the post-buckling behaviour of thin plates. It is well known that a thin flat plate undergoes secondary buckling after initial buckling took place and the deflection of the initial buckling mode was developed. From this point of view, this paper discusses the post-buckling behaviour of thin plates under thrust including the secondary buckling phenomenon. Series of elastic large deflection analyses were performed on rectangular plates with aspect ratio 3.6 using the analytical method and the FEM.

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Educational Needs Related to Home Management Perceived by Secondary Home Economics Teachers (가정과 교사의 중.고등학교 가정관리 교육내용에 대한 수업요구도와 관련변수에 관한 연구)

  • 이연숙
    • Journal of Korean Home Economics Education Association
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    • v.7 no.1
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    • pp.81-95
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    • 1995
  • The purpose of the study were to :(1)determine important home management concepts in the secondary home economics education curriculum, (2) identify the educational needs related to home management perceived by home economics teachers, and the factors affecting it. (3) use the findings to make recommendations for developing home economics curriculum and teaching home economics in the secondary school. The questionnaires were distributed to the 385 home economics teachers, lived in seoul, local cities and rural area. The data were analyzed by using descriptive statistics, t-test one way ANOVA with scheffe test, factor analysis, and multiple regression analysis. Forty home management concepts were selected based on the related literatures. Resource use, environmental concerns, consumer rights and consumer problems were the concepts which showed the highest level of educational needs perceived by the teachers. The educational needs were affected by school level, residence area of the respondents, age, career, and other factors related to the perception about home management education.

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Landscape Structure and Ecological Restoration of Mt. Hwangryung in Pusan, korea (부산시 황령산의 경관구조와 생태적 복원)

  • 이창석;조현제
    • The Korean Journal of Ecology
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    • v.21 no.6
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    • pp.791-797
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    • 1998
  • An attempt to clarify the landscape structure of urban areas was carried out on Mt. Hwangryung located in the center of Pusan, southern Korea. By means of aerial photographs and field survey, a vegetation map including land-use pattern was made. Landscape structure was described by analyzing the vegetation map. Landscape element types were classified into secondary forest, introduced plantation, and other elements including urbanized area. almus firma and Pinus thunbergii communities, introduced plantation elements, formed matrix and some secondary forest elements and the other artificial plantations of small scale tended to distribute as small patches in such matrix. The number of patches per unit area in secondary forest elements was more than that in introduced plantation element. The result on patech size was vice versa. As the results of landscape ecological analyses, it was estimated that differentiation of patches recognized in community level would be related to artificial interference and those in sub-communities levels to natural process such as progression of succession. On the other hand, restoration plans in viewpoints of restoration and landscape ecology were suggested to improve ecological quality of Mt. hwangryung.

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Predictive factors of substance misuse and abuse in South Korean adolescents: a secondary data analysis of the 2021 Youth Risk Behavior Web-based Survey

  • So Yeon Park
    • Child Health Nursing Research
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    • v.30 no.1
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    • pp.67-74
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    • 2024
  • Purpose: This study aimed to identify the general characteristics and health behaviors of students with non-therapeutic substance use. Methods: This secondary data analysis used data from the 17th Korea Youth Risk Behavior Web-based Survey (2021). Analyses of the 54,848 adolescents used descriptive statisics, the Rao-Scott χ2 test, and logistic regression. Results: The risk factors for substance use among students were anxiety, loneliness, living separately from family, suicidal ideation, e-cigarette use, and high stress. Conclusion: The findings help identify the risk factors for non-therapeutic drug use among adolescents. Since South Korea does not have a drug prevention program for its adolescent population, an educational plan based on these findings could help prevent adolescent substance abuse.

Secondary Structure and Phylogenetic Implications of ITS2 in the Genus Tricholoma

  • Suh, Seok-Jong;Kim, Jong-Guk
    • Journal of Microbiology and Biotechnology
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    • v.12 no.1
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    • pp.130-136
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    • 2002
  • The internal transcribed spacer (ITS) region in the genus Tricholoma was analyzed, including for its primary nucleotide sequence and secondary structural characterization. The secondary structures of the ITS2 region in the genus Tricholoma were identified for use in bioinformatic processes to study molecular evolution and compare secondary structures. Ten newly sequenced ITS regions were added to the analysis and submitted to the GenBank database. The resulting structure from a minimum energy algorithm indicated the four-domain model, as previously suggested by others. The conserved secondary structure of the ITS2 sequences of the genus Tricholoma exhibited certain unique features, including pyrimidine tracts in the loops of domain A and a complete structure containing four domains, with motifs identified in other ITS2 secondary structures. A phylogenetic tree was derived from sequence alignment based on the secondary structures. From the resulting maximum parsimonious tree, it was found that the species in the genus Tricholoma had evolved monophyletically and were composed of four groups, as supported by the bootstrapping values and pileus color.

An Anti-Interference Cooperative Spectrum Sharing Strategy with Joint Optimization of Time and Bandwidth

  • Lu, Weidang;Wang, Jing;Ge, Weidong;Li, Feng;Hua, Jingyu;Meng, Limin
    • Journal of Communications and Networks
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    • v.16 no.2
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    • pp.140-145
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    • 2014
  • In this paper, we propose an anti-interference cooperative spectrum sharing strategy for cognitive system, in which a secondary system can operate on the same spectrum of a primary system. Specifically, the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to achieve the target rate. To gain access to the spectrum of the primary system, the secondary system needs to allocate a fraction of bandwidth to help forward the primary signal. As a reward, the secondary system can use the remaining bandwidth to transmit its own signal. The secondary system uses different bandwidth to transmit the primary and its own signal. Thus, there will be no interference felt at primary and secondary systems. We study the joint optimization of time and bandwidth allocation such that the transmission rate of the secondary system is maximized, while guaranteeing the primary system, as a higher priority, to achieve its target transmission rate. Numerical results show that the secondary system can gain significant improvement with the proposed strategy.

FTA Effects of Secondary Auto-Part Venders in the Daegu Kyungpook Area (대구·경북지역 자동차 2차 부품기업의 FTA활용효과)

  • Kim, Heeho;Cho, Joo-Eun
    • Korea Trade Review
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    • v.44 no.3
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    • pp.253-269
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    • 2019
  • This study examines the utilization effect of FTA on the sales and profit of the secondary auto-part suppliers in two aspects: 1) firm-level survey on the utilization of FTA and 2) statistical inference on the FTA effects on their sales and profit. We use the GLS statistical technique, panel and survey data of 130 secondary auto-part suppliers in the Daegu and Kyungpook area in 2007-2016. The evidence shows that the secondary auto-part suppliers struggle to prepare documents for the FTA certificates of origin due to their small firm size, although they utilize the FTA at the relatively high rate of 92 percent. Statistical evidence shows that an increase in the export of the first vender significantly affects the sale of the secondary auto-part vendors, but not their profit. The low profit and high managing cost of utilizing the FTA deteriorate the utilization effect of the FTA of the secondary auto-part vendors, which is a key factor in a global supply chain and for the competitiveness of the automobile industry. Government policies are required for the secondary auto-part suppliers to utilize the FTA more effectively and share the benefits of tariff reduction with first auto-part vendors under FTA transaction.