• 제목/요약/키워드: Medium access

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Throughput 향상과 Fairness 보장을 위한 EDCF 기반의 MAC 알고리즘 연구 (The Study of MAC Algorithm Based on EDCF to Increase Throughput and Provide Fairness)

  • 김문;예휘진;노재성;조성준
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2005년도 춘계종합학술대회
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    • pp.578-582
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    • 2005
  • 본 논문에서는 Wireless Local Area Network (WLAN)에서 트래픽의 특성 및 네트워크 상태에 따른 Quality of Service (QoS)를 제공하기 위해 제안된 Medium Access Control (MAC) 알고리즘을 분석한다. 제안한 알고리즘은 네트워크 상태를 나타내는 ACK Ratio (AR)를 사용하여 Backoff 알고리즘에 적용할 뿐 아니라, Inter Frame Space (IFS)를 적응적으로 변화시킴으로서 매체 이용률을 높여주어, Throughput을 향상시키고 최소한의 Fairness를 제공한다. 또한, Network Simulator-2(NS-2)를 사용하여 기존의 MAC 알고리즘과 제안하는 MAC 알고리즘의 성능을 분석한다.

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개별성과측정시스템의 주요성과지표 설계 연구 (Design of KPI on Individual Performance Measurement System)

  • 홍현기;오상영
    • 한국산학기술학회논문지
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    • 제9권3호
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    • pp.815-821
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    • 2008
  • 기업의 성과는 기업이 갖고 있는 유형, 무형의 자산 운용 결과이므로 성과측정은 유형, 무형의 모든 측면에서 이루어져야 할 것이다. 그러나 측정하고자 하는 대상이 반드시 정량적 결과를 확보하고 있다는 보장이 없으므로 객관적 성과측정에 대한 신뢰를 확보하기가 쉽지는 않다. 특히 대기업과 중소기업의 조직 생성과 운용 방식이 근본적으로 상이하므로 측정 방식도 다를 수밖에 없다. 본 연구는 중소기업에 적합한 성과측정의 관점을 직무, 태도, 능력, 자격의 관점으로 제시하였으며 조직성과측정보다는 개별측정 방식을 권고하였다. 또한 시스템의 구성은 사용자와 팀장 및 BSC 담당자로 구성하여 BSC 서버를 중심으로 각 사용자의 인터넷 계정을 통하여 입력하고, 평가하고, 승인할 수 있도록 하였다.

Foreign Direct Investment -Small and Medium Enterprises Linkages and Global Value Chain Participation: Evidence from Vietnam

  • NGUYEN, Thi Minh Thu;NGUYEN, Thi Tuong Anh;NGUYEN, Thi Thuy Vinh;PHAM, Huong Giang
    • The Journal of Asian Finance, Economics and Business
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    • 제8권3호
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    • pp.1217-1230
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    • 2021
  • Using a multinomial logit model with the panel-data set of Vietnam manufacturing firms, this paper investigates the impacts of foreign direct investment (FDI) - small and medium enterprises (SMEs) linkages and other factors on SMEs' participation in the global value chain (GVC). We consider GVC firms are those engaging in any of the three modes including (i) using domestic inputs to export (D2E), (ii) using imported inputs to produce for the domestic market (I2P), (iii) using imported inputs to export (I2E). We discover that FDI-SME linkages statistically encourage Vietnamese SMEs to integrate into the GVC via I2P and I2E, while no statistical association between FDI-SME linkage and D2E participation is found. GVCs participation likelihood is also positively correlated with the introduction of new product introduction. The establishment of firms' production facilities in industrial zones and foreign ownership are both reported to be significantly decisive factors to SMEs' decisions on GVC participation. Besides, there is a strong association between firms' attributes, i.e. employment, capital intensity as well as financial access, and their participation in the GVC. Local governance quality (proxied by the Provincial Competitiveness Index) and the share of skilled labor at the province-level can facilitate firms' integration into GVCs, while greater market concentration may be a hurdle to such potential.

Evaluation of Accounting Information Quality of Small and Medium-Sized Enterprises: An Empirical Study in Vietnam

  • NGUYEN, Thi Thu Cuc;HO, My Hanh
    • The Journal of Asian Finance, Economics and Business
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    • 제8권7호
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    • pp.161-167
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    • 2021
  • Nowadays, small- and medium-sized enterprises (SMEs) are placed among the key components of the economy in both developed and developing countries. They are internationally known as the driving force based on their enormous contributions to Gross Domestic Product (GDP) and generating new employment. They are generally presumed as the leader of environmental sustainability, economic prosperity, and innovation, particularly for the economy of developing countries such as Vietnam. However, SMEs have difficulty in raising capital, as well as access to credit. One of the reasons is that there are inadequacies in accounting information quality in SMEs as well as the provision of accounting information and accounting information confidentiality. The main objective of this study was to identify, evaluate, and measure the attributes of accounting information quality of SMEs in Hanoi. The study was based on a field survey using a semi-structured questionnaire on a sample of 150 accountants. The study has identified and measured six (6) attributes of accounting information quality of SMEs that have great effects on accountants. There is, statistically, no significant difference in the level of accounting information quality of SMEs in Hanoi from these different business areas. There is no, statistically, significant difference in the level of accounting information quality of SMEs in Hanoi between the mentioned three groups of the job description. Based on the findings, some recommendations are given for SMEs to improve accounting information quality.

Quality of Service using Min-Max Data Size Scheduling in Wireless Sensor Networks

  • Revathi, A.;Santhi, S.G.
    • International Journal of Computer Science & Network Security
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    • 제22권9호
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    • pp.327-333
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    • 2022
  • Wireless Sensor Networks (WSNs) plays an important role in our everyday life. WSN is distributed in all the places. Nowadays WSN devices are developing our world as smart and easy to access and user-friendly. The sensor is connected to all the resources based on the uses of devices and the environment [1]. In WSN, Quality of Service is based on time synchronization and scheduling. Scheduling is important in WSN. The schedule is based on time synchronization. Min-Max data size scheduling is used in this proposed work. It is used to reduce the Delay & Energy. In this proposed work, Two-hop neighboring node is used to reduce energy consumption. Data Scheduling is used to identify the shortest path and transmit the data based on weightage. The data size is identified by three size of measurement Min, Max and Medium. The data transmission is based on time, energy, delivery, etc., the data are sent through the first level shortest path, then the data size medium, the second level shortest path is used to send the data, then the data size is small, it should be sent through the third level shortest path.

Measurement and Impact of Virtual and Digital Marketing as a Distribution Channel in Business

  • Fatos UKAJ;Vehbi RAMAJ;Shaqir ELEZAJ
    • 유통과학연구
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    • 제21권5호
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    • pp.1-9
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    • 2023
  • Purpose: Marketing and especially distribution channels has proved challenging for small and medium-sized enterprises (SMEs) worldwide due to its exorbitant cost. The objective of this study is to access the role and impact of digital marketing as a new distribution channel in companies located in Kosovo. Research design, data and methodology: To achieve the objective of the research, data was collected from 64 respondents/participants working in different organizations and sectors. Results: The result of the data collected showed that digital marketing plays a huge role and an effective medium in distribution of products and services, and helps in boosting sales of companies. The results showed that this form of marketing helps with retention of customers and cost effectiveness. Conclusions: The managerial implication of this study is that it is believed that customers in the topical conversation region are impacted by Kosovo businesses and their online marketing initiatives. The results of this study suggest that marketers and managers should take advantage of social media in order to accomplish the study's main objective. However, for enhanced productivity and high-level effectiveness of Digital marketing in Kosovo, there should be proper sensitization on the available digital marketing options and how it can be done.

관계금융이 중소기업의 수출에 미치는 영향에 관한 연구 (Relationship Banking and Exports: Evidence from SMEs in the Korean Stock Markets)

  • 임정대
    • 무역학회지
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    • 제45권5호
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    • pp.1-22
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    • 2020
  • This study explores the role of relationship banking for the exports of SMEs (small and medium sized enterprises) in Korea. Using a sample of SMEs listed on the Korean stock markets between 2004 and 2018, I find that relationship banking has a positive impact on exporting behaviors of SMEs. This result indicates that relationship banking is suitable for SMEs to raise their funds in the export decision-making since the incentive for banks to obtain soft information enhances SMEs' access to external finance. In particular, through further analysis considering financial constraints, I find that the positive impact of relationship banking on exports is amplified for financially constrained SMEs. In addition, the positive impact on exports is also amplified for export starters. Finally, relationship banking provides benefits for SMEs' export decision-making regardless of the financial crisis. To sum up, relationship banking may be useful means of financing for Korean SMEs whose creditworthiness cannot be assessed only by hard information. As the role of finance in international trade has recently been highlighted, this study provides insightful evidence that relationship banking may enhance exports of SMEs as a source of trade finance.

수조 및 저수지 실험을 통한 수중 코드 분할 다중 접속 기법 순방향 링크 성능 분석 (Performance Evaluation of Underwater Code Division Multiple Access Scheme on Forward-Link through Water-Tank and Lake Experiment)

  • 서보민;손권;조호신
    • 한국통신학회논문지
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    • 제39C권2호
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    • pp.199-208
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    • 2014
  • 코드 분할 다중 접속 기법은 주파수 선택적 페이딩에 강인하고 높은 주파수 재사용 효율 특성으로 인해 열악한 수중 환경에서의 유망한 매체 접속 제어 기법으로 많은 연구가 진행되고 있다. 또한 최근 수중 매체 접속 제어기법의 성능 분석이 모의실험을 통해서 뿐만 아니라 해상 및 저수지에서의 실제 실험을 통해 이뤄지고 있다. 이에 본 논문에서는 수중 코드 분할 다중 접속 기법의 순방향 링크에 대한 트랜스시버를 설계한다. 수조 실험을 통해 코드 분할 다중 접속 기법의 수중 환경 적용 가능성을 검증하며, 수조 실험으로 얻어진 결과를 바탕으로 개선된 성능의 트랜스시버를 설계하고 모의실험과 저수지 실험을 통해 성능 개선을 확인한다. 사용자 데이터는 월시 부호를 사용하여 다중화되며, PN 획득 과정을 통해 위상 오류 정정 및 PN 부호 역확산을 수행한다. 또한 성능 향상을 위해 인터리빙 기법과 높은 오류 정정 효율을 가지는 채널 부호화 기법을 사용한다. 결과적으로 두 개의 다중화 데이터는 모두 오류 없이 복원되었으며, 세 개, 네 개의 다중화 데이터는 15% 이하의 오류율로 복원되었다.

Heavy-Ion Radiation Characteristics of DDR2 Synchronous Dynamic Random Access Memory Fabricated in 56 nm Technology

  • Ryu, Kwang-Sun;Park, Mi-Young;Chae, Jang-Soo;Lee, In;Uchihori, Yukio;Kitamura, Hisashi;Takashima, Takeshi
    • Journal of Astronomy and Space Sciences
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    • 제29권3호
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    • pp.315-320
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    • 2012
  • We developed a mass-memory chip by staking 1 Gbit double data rate 2 (DDR2) synchronous dynamic random access memory (SDRAM) memory core up to 4 Gbit storage for future satellite missions which require large storage for data collected during the mission execution. To investigate the resistance of the chip to the space radiation environment, we have performed heavy-ion-driven single event experiments using Heavy Ion Medical Accelerator in Chiba medium energy beam line. The radiation characteristics are presented for the DDR2 SDRAM (K4T1G164QE) fabricated in 56 nm technology. The statistical analyses and comparisons of the characteristics of chips fabricated with previous technologies are presented. The cross-section values for various single event categories were derived up to ~80 $MeVcm^2/mg$. Our comparison of the DDR2 SDRAM, which was fabricated in 56 nm technology node, with previous technologies, implies that the increased degree of integration causes the memory chip to become vulnerable to single-event functional interrupt, but resistant to single-event latch-up.

HFC CATV 망의 전송 및 데이터 통신

  • 황승오;박종헌;박승권
    • 정보와 통신
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    • 제15권7호
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    • pp.75-94
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    • 1998
  • 본 논문에서는 현재 초고속정보통신망의 하부 가입자망으로 제시되고 있는 HFC CATV망, ADSL, B-WLL 중에서 현실적으로 우리 나라에 가장 타당한 방식으로 떠오르고 있는 HFC CATV망에 대하여 소개하였다. 다른 망에 비해 HFC CATV망이 갖는 장점은 기존의 가입자망(PSTN)보다 훨씬 넓은 양?향 대역폭을 갖고 있으며, 이미 가입자단까지 포설이 되어 있어 초기 투자비용이 적다는 것이다. 또한 본 논문에서는 HFC CATV망의 구조와 채널 환경의 문제점과 해결책, 데이터 전송방법, 매체접속 제어, IEEE 802.14, MCNS 등의 표준화 동향, 국내외 CATV망을 사용한 부가통신 서비스 동향 등을 살펴보았다. 그리고 기간망과 가입자망으로서 HFC CATV망과의 연동, 국내 HFC CATV망을 이용한 디지털 신호 전송능력 평가를 자세히 소개하였다. 이 전송능력 평가에서 셀당 500 가입자 정도로 셀 재분할이 이루어진다면 유입잡음이 줄어들게 되어 다양한 부가서비스의 QoS를 만족시킬 수 있다는 것이 확인 되었다. 이와 같은 내용을 바탕으로 초고속 정보통신망의 하부 가입자 접속망으로써 HFC CATV망이 제시되어졌다.

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