• 제목/요약/키워드: Challenge Model

검색결과 864건 처리시간 0.029초

Joint Subcarriers and Power Allocation with Imperfect Spectrum Sensing for Cognitive D2D Wireless Multicast

  • Chen, Yueyun;Xu, Xiangyun;Lei, Qun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권7호
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    • pp.1533-1546
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    • 2013
  • Wireless multicast is considered as an effective transmission mode for the future mobile social contact services supported by Long Time Evolution (LTE). Though wireless multicast has an excellent resource efficiency, its performance suffers deterioration from the channel condition and wireless resource availability. Cognitive Radio (CR) and Device to Device (D2D) are two solutions to provide potential resource. However, resource allocation for cognitive wireless multicast based on D2D is still a great challenge for LTE social networks. In this paper, a joint sub-carriers and power allocation model based on D2D for general cognitive radio multicast (CR-D2D-MC) is proposed for Orthogonal Frequency-Division Multiplexing (OFDM) LTE systems. By opportunistically accessing the licensed spectrum, the maximized capacity for multiple cognitive multicast groups is achieved with the condition of the general scenario of imperfect spectrum sensing, the constrains of interference to primary users (PUs) and an upper-bound power of secondary users (SUs) acting as multicast source nodes. Furthermore, the fairness for multicast groups or unicast terminals is guaranteed by setting a lower-bound number of the subcarriers allocated to cognitive multicast groups. Lagrange duality algorithm is adopted to obtain the optimal solution to the proposed CR-D2D-MC model. The simulation results show that the proposed algorithm improves the performance of cognitive multicast groups and achieves a good balance between capacity and fairness.

사회-기술 시스템 전환과 기업 혁신활동 (Socio-Technological System Transition and Innovation Activities of Firms)

  • 황혜란;송위진
    • 기술혁신연구
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    • 제22권4호
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    • pp.57-88
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    • 2014
  • 글로벌 수준에서의 환경, 경제, 사회적 차원의 거대한 도전은 이제까지의 이윤추구 위주의 기업 활동에 근본적인 질문을 제기하고 있다. 기업은 경제적 주체임과 동시에 사회적, 환경적 책무를 가진 사회적 주체로 인식되고 있다. 특히 사회-기술 시스템 전환을 지향하는 기업 활동이 새로운 현상으로 발흥함에 따라 기업의 정체성, 활동 동기와 비즈니스 모델 진화에 대한 기술혁신 관점에서의 확장된 논의가 요청된다. 본 논문은 지속가능한 시스템 전환에 있어 기업의 역할에 주목하고, '전환지향적 기업' 개념을 제출함으로써 기존의 경제적 관점에서만 고려되어온 기업의 개념을 사회적 문맥 하에서 재해석하려는 목적을 가지고 있다. 본 논문은 기업이 전환활동에 참여하는 동기, 비즈니스 모델의 유형 및 전환을 위한 조직 및 전략 등에 대한 기존 논의들을 검토함으로써 전환지향적 기업 활동의 새로운 범주의 이해에 기여하고자 한다. 이론 및 사례에 대한 문헌연구를 통해 시스템 전환을 지향하는 비즈니스 모델 혁신의 유형을 크게 기술적 혁신, 조직적 혁신, 사회적 혁신의 세 가지 차원으로 구분하고 각 유형별 특징을 도출하였다. 또한 전환지향적 기업 활동을 전개함에 있어 기술(인지)적, 조직적, 시스템적 차원에서 장애요인에 직면할 수 있음을 지적하고 이를 극복하기 위해서는 장기적 관점에서의 기업전략과 시스템 전환을 지원하는 정책노력이 필요함을 주장하였다.

Active Immunization Study of Colon Cancer Derived 1-8D Peptide in HHD Mice

  • Jung, Hun-Soon;Ahn, In-Sook;Do, Hyung-Ki;Lemonnier, Francois A.;Song, Kuk-Hyun;Do, Myoung-Sool
    • IMMUNE NETWORK
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    • 제5권3호
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    • pp.157-162
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    • 2005
  • Background: 1-8D gene is a member of human 1-8 interferon inducible gene family and was shown to be overexpressed in fresh colon cancer tissues. Three peptides 1-6, 3-5 and 3-7 derived from human 1-8D gene were shown to have immunogenicity against colon cancer. Methods: To study tumor immunotherapy, of three peptides we established an active immunization model using HHD mice. $D^{b-/-}{\times}{\beta}2$ microglobulin $({\beta}2m)$ null mice transgenic for a chimeric HLA-$A2.1/D^{b-}\;{\beta}2m$ single chain (HHD mice) were challenged with B16/HHD/1-8D tumor cells and were immunized with irradiated peptide-loaded RMA- S/HHD/B7.1 transfectants. In therapy model tumor growth was retarded in HHD mice that were injected with 3-5 peptide-loaded RMA-S/HHD/B7.1. In survival test vaccination with 1-8D-derived peptide protects HHD mice from tumor progression after tumor challenge. Results: These studies show that peptide 3-5 derived from 1-8D gene can be the most effective candidate for the vaccine of immunotherapy against colon cancer and highlight 1-8D gene as putative colon carcinoma associated antigens. Conclusion: We demonstrated that RMA-S/HHD/ B7.1 loaded with 1-8D peptides, especially 3-5, immunization generates potent antitumor immunity against tumor cells in HHD mice and designed active immunization as proper immunotherapeutic protocols.

A comparison of deep-learning models to the forecast of the daily solar flare occurrence using various solar images

  • Shin, Seulki;Moon, Yong-Jae;Chu, Hyoungseok
    • 천문학회보
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    • 제42권2호
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    • pp.61.1-61.1
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    • 2017
  • As the application of deep-learning methods has been succeeded in various fields, they have a high potential to be applied to space weather forecasting. Convolutional neural network, one of deep learning methods, is specialized in image recognition. In this study, we apply the AlexNet architecture, which is a winner of Imagenet Large Scale Virtual Recognition Challenge (ILSVRC) 2012, to the forecast of daily solar flare occurrence using the MatConvNet software of MATLAB. Our input images are SOHO/MDI, EIT $195{\AA}$, and $304{\AA}$ from January 1996 to December 2010, and output ones are yes or no of flare occurrence. We consider other input images which consist of last two images and their difference image. We select training dataset from Jan 1996 to Dec 2000 and from Jan 2003 to Dec 2008. Testing dataset is chosen from Jan 2001 to Dec 2002 and from Jan 2009 to Dec 2010 in order to consider the solar cycle effect. In training dataset, we randomly select one fifth of training data for validation dataset to avoid the over-fitting problem. Our model successfully forecasts the flare occurrence with about 0.90 probability of detection (POD) for common flares (C-, M-, and X-class). While POD of major flares (M- and X-class) forecasting is 0.96, false alarm rate (FAR) also scores relatively high(0.60). We also present several statistical parameters such as critical success index (CSI) and true skill statistics (TSS). All statistical parameters do not strongly depend on the number of input data sets. Our model can immediately be applied to automatic forecasting service when image data are available.

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IoT기반 피트니스 트래커의 사용의도에 영향을 미치는 요인에 관한 연구 (A Study on Factors Affecting the Intention of Using IoT-Based Fitness Tracker)

  • 조덕윤;한경석
    • 디지털콘텐츠학회 논문지
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    • 제19권9호
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    • pp.1717-1726
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    • 2018
  • 본 연구는 플로우이론과 UTAUT모형에 의한 IoT기반 피트니스 트래커의 이용의도에 영향을 미치는 요인을 알아보고자 한다. IoT기반 피트니스 트래커의 독립변수들로 플로우 경험이론에서 사용된 도전감과 숙련도 요인을 활용하고 개인적 특성인 건강관심도와 유희성 그리고 사회적 영향, 촉진조건을 선정하였다. 또한 UTAUT이론을 활용하여 성과기대와 노력기대를 매개변수로 활용하였으며 종속변수로는 사용의도를 선정하였다. 이러한 연구가설을 검증하기 위하여 본 연구는 126개의 설문자료를 수집하고 Smart PLS를 활용하여 통계적 분석을 실시하였다. 연구결과, 통합기술수용모델 (UTAUT)의 주요변수와 더불어 본 연구에서 새롭게 도입한 플로우 경험과 개인적 특성요인이 IoT기반 피트니스 웨어러블 환경에서도 유의한 영향을 미치는 것으로 나타났다.

Plant breeding in the 21st century: Molecular breeding and high throughput phenotyping

  • Sorrells, Mark E.
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.14-14
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    • 2017
  • The discipline of plant breeding is experiencing a renaissance impacting crop improvement as a result of new technologies, however fundamental questions remain for predicting the phenotype and how the environment and genetics shape it. Inexpensive DNA sequencing, genotyping, new statistical methods, high throughput phenotyping and gene-editing are revolutionizing breeding methods and strategies for improving both quantitative and qualitative traits. Genomic selection (GS) models use genome-wide markers to predict performance for both phenotyped and non-phenotyped individuals. Aerial and ground imaging systems generate data on correlated traits such as canopy temperature and normalized difference vegetative index that can be combined with genotypes in multivariate models to further increase prediction accuracy and reduce the cost of advanced trials with limited replication in time and space. Design of a GS training population is crucial to the accuracy of prediction models and can be affected by many factors including population structure and composition. Prediction models can incorporate performance over multiple environments and assess GxE effects to identify a highly predictive subset of environments. We have developed a methodology for analyzing unbalanced datasets using genome-wide marker effects to group environments and identify outlier environments. Environmental covariates can be identified using a crop model and used in a GS model to predict GxE in unobserved environments and to predict performance in climate change scenarios. These new tools and knowledge challenge the plant breeder to ask the right questions and choose the tools that are appropriate for their crop and target traits. Contemporary plant breeding requires teams of people with expertise in genetics, phenotyping and statistics to improve efficiency and increase prediction accuracy in terms of genotypes, experimental design and environment sampling.

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UNCITRAL 중재규칙 개정안의 내용과 쟁점에 관한 연구 (A Study on the Draft and Issues for the Revision of UNCITRAL Arbitration Rules)

  • 이강빈
    • 한국중재학회지:중재연구
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    • 제17권2호
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    • pp.43-70
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    • 2007
  • The purpose of this paper is to make research on the contents and discussions of the draft of revised UNCITRAL Arbitration Rules that have been discussed and considered by the Working Group. At its thirty-ninth session (New York, 19 June-7 July 2006), the Commission agreed that, in respect of future work of the Working Group, priority be given to a revision of the UNCITRAL Arbitration Rules (1976). At its forty-fifth session (Vienna, 11-15 September 2006), the Working Group undertook to identify areas where a revision of the UNCITRAL Arbitration Rules might be useful. At that session, it was considered that the focus of the revision should be on updating the Rules to meet changes that had taken place over the last thirty years in arbitral practice. The largely amended provisions of the draft of revised UNCITRAL Arbitration Rules are as follows : Notice of arbitration and response to the notice of arbitration (Article 3), Designating and appointing authorities (Article 4 bis), November of arbitrators (Article 5), Appointment of arbitrations (Article 6), Appointment of arbitrators in multi-party arbitration (Article 7 bis), Challenge of arbitrators (Article 9), Replacement of an arbitrator (Article 13), Pleas as to the jurisdiction of the arbitral tribunal (Article 21), Interim measures (Article 26), Form and effect of the award (Article 32), and Liability of arbitrators (Proposed additional provisions). There are some differences between the draft of revised UNCITRAL Arbitration Rules and the KCAB Arbitration Rules. In order to jnternationalize the Korea's commercial arbitration system, it is desirable that the main articles of the draft of revised UNCITRAL Arbitration Rules should be admitted to the KCAB Arbitration Rules. In conclusion, the Commission was generally of the view of any revision of the UNCITRAL Arbitration Rules should not alter the structure of the text, its spirit, its drafting style, and should respect the flexibility of the text rather than make it more complex. The Working Group agreed that harmonizing the provisions of the UNCITRAL Model Law should not be automatic but rather considered only where appropriate.

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Moving Mass Actuated Reentry Vehicle Control Based on Trajectory Linearization

  • Su, Xiao-Long;Yu, Jian-Qiao;Wang, Ya-Fei;Wang, Lin-lin
    • International Journal of Aeronautical and Space Sciences
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    • 제14권3호
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    • pp.247-255
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    • 2013
  • The flight control of re-entry vehicles poses a challenge to conventional gain-scheduled flight controllers due to the widely spread aerodynamic coefficients. In addition, a wide range of uncertainties in disturbances must be accommodated by the control system. This paper presents the design of a roll channel controller for a non-axisymmetric reentry vehicle model using the trajectory linearization control (TLC) method. The dynamic equations of a moving mass system and roll control model are established using the Lagrange method. Nonlinear tracking and decoupling control by trajectory linearization can be viewed as the ideal gain-scheduling controller designed at every point along the flight trajectory. It provides robust stability and performance at all stages of the flight without adjusting controller gains. It is this "plug-and-play" feature that is highly preferred for developing, testing and routine operating of the re-entry vehicles. Although the controller is designed only for nominal aerodynamic coefficients, excellent performance is verified by simulation for wind disturbances and variations from -30% to +30% of the aerodynamic coefficients.

선수 규칙파 중 만재상태의 KVLCC2 모형선 공칭반류 계측 (Nominal Wake Measurement for KVLCC2 Model Ship in Regular Head Waves at Fully Loaded Condition)

  • 김호;장진호;황승현;김명수
    • 대한조선학회논문집
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    • 제53권5호
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    • pp.371-379
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    • 2016
  • In the ship design process, ship motion and propulsion performance in sea waves became very important issues. Especially, prediction of ship propulsion performance during real operation is an important challenge to ship owners for economic operation in terms of fuel consumption and route-time evaluation. Therefore, it should be considered in the early design stages of the ship. It is thought that the averaged value and fluctuation of effective inflow velocity to the propeller have a great effect on the propulsion performance in waves. However, even for the nominal velocity distribution, very few results have been presented due to some technical difficulties in experiments. In this study, flow measurements near the propeller plane using a stereo PIV system were performed. Phase-averaged flow fields on the propeller plane of a KVLCC2 model ship in waves were measured in the towing tank by using the stereo PIV system and a phase synchronizer with heave motion. The experiment was carried out at fully loaded condition with making surge, heave and pitch motions free at a forward speed corresponding to Fr=0.142 (Re=2.55×106) in various head waves and calm water condition. The phase averaged nominal velocity fields obtained from the measurements are discussed with respect to effects of wave orbital velocity and ship motion. The low velocity region is affected by pressure gradient and ship motion.

자료포락분석을 이용한 전기차 충전소 운영효율성 평가 (Evaluation of Operational Efficiency for Electric Vehicle Charging Stations Using Data Envelopment Analysis)

  • 손동훈;강영수;김화중
    • 산업경영시스템학회지
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    • 제43권3호
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    • pp.53-60
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    • 2020
  • Evaluating the operational efficiency of electric vehicle charging stations (EVCSs) is important to understand charging network evolution and the charging behavior of electric vehicle users. However, aggregation of efficiency performance metrics poses a significant challenge to practitioners and researchers. In general, the operational efficiency of EVCSs can be measured as a complicated function of various factors with multiple criteria. Such a complex aspect of managing EVCSs becomes one of the challenging issues to measure their operational efficiency. Considering the difficulty in the efficiency measurement, this paper suggests a way to measure the operational efficiency of EVCSs based on data envelopment analysis (DEA). The DEA model is formulated as constant returns of output-oriented model with five types of inputs, four of them are the numbers of floating population and nearby charging stations, distance of nearby charging stations and traffic volume as desirable inputs and the other is the traffic speed in congestion as undesirable one. Meanwhile, the output is given by the charging frequency of EVCSs in a day. Using real-world data obtained from reliable sources, we suggest operational efficiencies of EVCSs in Seoul and discuss implications on the development of electric vehicle charging network. The result of efficiency measurement shows that most of EVCSs in Seoul are inefficient, while some districts (Nowon-gu, Dongdaemun-gu, Dongjak-gu, Songpa-gu, Guro-gu) have relatively more efficient EVCSs than the others.