• Title/Summary/Keyword: Link quality

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History of Organic Agricultural Movement and Perspective for Development of Organic Agriculture in Tasmania (호주 태즈메이니아 유기농운동의 전개과정과 발전과제)

  • Kim, J.S.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.15 no.1
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    • pp.25-43
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    • 2013
  • Tasmania with its clean air, isolated from mainland Australia, has been producing high-quality agricultural products and has been continually developing organic farming since 1946 when the Living Soil Association of Tasmania(LSAT) was established. The organic farming movement in Tasmania has been actively advocated through three steps: the philosophical embryonic period, the movement diffusion period and the industrialised development period. The campaigns for informing about the connection between healthy soil and life unfolded during the embryonic period. This was followed by the birth of publicity of organic farming and the certification system through the dissemination of organic farming techniques and various events related to agriculture in the diffusion period when the Organic Gardening and Farming Society(OGFS) was established in 1972. In the industrialised development period, The Organic Coalition of Tasmania (OCT) which is representative of Tasmania was organised in 2000 and has been leading the organic farming industry. The organic farming movement in Tasmania not only limits the use of artificial agricultural chemical but pursues the quality of food, environment, the health of life including all animals and plants, the issue of development in rural society, social justice, and equity in understanding. It is far more holistic in its philosophy. The output of organic food accounts for 1 % of the total amount of agricultural production and 150 certified organic farms have managed with 5,000ha of land in 2010. The supply channels for organic foods vary from farmer's market, specialty stores, supermarket chains, local store to the cooperative community. Also the consumers' behaviour for organic foods has been establishing as an alternative life style. The education of the value and role of organic farming on the environment should be enlarged for the consumption of the organic food. In addition, organising for small farmers who act individually and the link with differentiated local food have still remained issues.

Effect of a cell loading on the soft handoff of a DS-CDMA cellular system (Cell loading이 D-CDMA 셀룰러 시스템의 소프트 핸드오프에 미치는 영향)

  • 김경민;김남수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.8A
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    • pp.1223-1230
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    • 2000
  • In this paper, we proposed a handoff decision method based on signal-to-interference ratio(SIR) of the pilot channel in order to perform a handoff more effectively and to complement disadvantages - deterioration quality of a call, decreasing capacity of the system, and wasting power of the mobile station - which is caused when handoff is performed by the classical method that execute a handoff based on received signal strength. Moreover, when we change that the minimum threshold, the cell loading which is defined active traffic channels to total traffic channels ratio, and the fraction of the transmit power from base station allocated to the pilot channel on the forward link of a DS-CDMA system, we analyzed mean numbers of handoff depending on hysteresis level during the mobile station moving from one base station to another base station.

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A New Class-Based Traffic Queue Management Algorithm in the Internet

  • Zhu, Ye
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.3 no.6
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    • pp.575-596
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    • 2009
  • Facing limited network resources such as bandwidth and processing capability, the Internet will have congestion from time to time. In this paper, we propose a scheme to maximize the total utility offered by the network to the end user during congested times. We believe the only way to achieve our goal is to make the scheme application-aware, that is, to take advantage of the characteristics of the application. To make our scheme scalable, it is designed to be class-based. Traffic from applications with similar characteristics is classified into the same class. We adopted the RED queue management mechanism to adaptively control the traffic belonging to the same class. To achieve the optimal utility, the traffic belonging to different classes should be controlled differently. By adjusting link bandwidth assignments of different classes, the scheme can achieve the goal and adapt to the changes of dynamical incoming traffic. We use the control theoretical approach to analyze our scheme. In this paper, we focus on optimizing the control on two types of traffic flows: TCP and Simple UDP (SUDP, modeling audio or video applications based on UDP). We derive the differential equations to model the dynamics of SUDP traffic flows and drive stability conditions for the system with both SUDP and TCP traffic flows. In our study, we also find analytical results on the TCP traffic stable point are not accurate, so we derived new formulas on the TCP traffic stable point. We verified the proposed scheme with extensive NS2 simulations.

The Influences of Technological Innovation and Cost Management for Elevation of Small Enterprise Competitiveness on Productivity : Focused on Marine Engine Suppliers (중소기업 경쟁력 향상을 위한 기술혁신 및 원가관리가 생산성에 미치는 영향 : 선박엔진 부품제조업체를 중심으로)

  • Lee, Seol Bin;Baek, Dong Hyun
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.4
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    • pp.9-17
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    • 2013
  • The purpose of this study is to figure out the impacts of technological innovation and cost management on productivity in small shipping industries to come up with developmental implications. To achieve this, a survey was carried out to 150 workers in small shipbuilding industries through April 2 to April 20, 2012. As for findings stated above, technological innovation and cost management in the Korean small shipbuilding industries were key factors that elevate financial and non-financial productivity. In the light of low technological prowess and cost structure of small shipbuilding industries, their productivity can be improved when intensive cost management with production factor technology as know-how is realized through quality management, which product development technology is the top priority as an independent niche strategy. Consequently, the combination of infrastructures in small shipbuilding industries with continuous efforts for cost reduction by the link to the systematized structure can't only secure their independent competitiveness, but raise their productivity.

Effect of Path Loss Models for CDMA Base Station Deployment in LOS Environments (LOS 환경에서 CDMA 기지국 배치를 위한 Path Loss Model의 영향)

  • Min, Seung-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.1A
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    • pp.1-7
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    • 2011
  • Cell Capacity and cell layout are strongly dependent on the up-link interference caused by out-of-cell mobiles. Accurate prediction of the propagation path loss from out-of-cell mobiles is essential to achieve system designs that minimize the infrastructure required for a given quality of service (QOS). Less accurate predictions can be expected to yield designs requiring the use of a greater number of base stations. In order to quantify the dependence of infrastructure on prediction accuracy, this paper considers the cellular systems, LOS (line of sight) cells along a road or highway.

Symbolic Interaction and Consumer products by mass media (미디어매체에 의한 제품과 상징의 상호작용에 관한 분석)

  • Song, Gyeong-Seok
    • 한국디지털정책학회:학술대회논문집
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    • 2005.06a
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    • pp.505-516
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    • 2005
  • According to Mead's (1934) symbolic interaction theory, social roles are learned through interaction and experiences in everyday life. Over time, these rules of behavior become internalized and serve to structure one's actions accordingly. Ultimately, these rules provide us with a powerful means of controlling our actions, and in time, they define our identity. Transforming the socialization process is one's conscious interpretation of stimuli through the use of symbols. Furthermore, society's perceptual processes can be shaped by the symbols we learn. The meaning of symbols can be learned from a variety of social influences, one of which may be mediated messages and advertising. This paper attempts to establish a link between media exposure and one's perception of social reality regarding character judgments made of unknown others based on the target's product or brand usage. Using magazine advertisements for fictitious products, the experiment herein seeks to establish two fundamental goals: 1) to determine if perceptions can be manipulated via association with companion symbolic elements: and 2) to detect whether television exposure is a moderating factor. Respondents were asked their perceptions of both product quality and of product users.

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Performance Analysis of Physical Layer Security based on Decode-and-Forward using Jammer (재머를 사용하는 복호 후 재전송 기반 물리 계층 보안의 성능 분석)

  • Park, Sol;Kong, Hyung-Yun
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.3
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    • pp.71-75
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    • 2018
  • In this paper, we study the secrecy outage probability when using jammer in a relay system based on decode-and-forward. The jammer may be selected among the relays not selected to increase the security capacity in the physical layer so as to generate intentional noise. Jammer noise can equally interfere with the receiver and eavesdropper but can enhance the physical layer security by selecting an optimal jammer that makes the channel quality between the sender-eavesdropper links worse than the channel of the sender-receiver link. In this paper, we compute the theoretical formula of the secrecy outage probability with and without jammers, and compare the theoretical value with the simulation value to prove that the equation is valid.

Development of Protocols for School Health Practice: Focusing on Primary School (학교보건 실무 프로토콜 개발: 초등학교를 대상으로)

  • Kim, Jin Hee;So, Hyang Sook
    • Journal of the Korean Society of School Health
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    • v.32 no.3
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    • pp.152-164
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    • 2019
  • Purpose: This study was a descriptive methodological study to develop protocols for school health practice to manage health problems of primary school students effectively. Methods: The protocols were verified by 12 experts and 10 health teachers, respectively, to secure a two-step content validity. Results: The main 8 health problems of primary school students were headache, abdominal pain, musculo-skeletal, respiratory, circulatory, ophthalmic, and oral-dental problems, and fever. The developed protocols consist of 8 algorithms, which are to help decision making in the course of assessing health problems and to identify and link related factors and associated symptoms, 8 school nursing records based on the Omaha classification system, and the list of 441 links between nursing assessment and nursing intervention. Conclusion: The use of the protocols is expected to make it easier for health teachers to apply the nursing process in solving the health problems of primary school students and supporting the rational decision making process, eventually improving the quality of primary school health. Repeated studies for protocol standardization as well as studies dealing with various health problems not included in the protocols should be performed for the development of school health practice protocols.

A Numerical Algorithm for Evaluating Progression Efficiency along Coordinated Arterials Using Shock Wave Theory (충격파이론을 응용한 간선도로 신호연동화의 효율 평가를 위한 알고리즘의 개발)

  • Kim, Young-Chan;Baek, Hyon-Su
    • Journal of Korean Society of Transportation
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    • v.17 no.2
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    • pp.83-90
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    • 1999
  • A computer algorithm is presented that evaluate the performance of coordinated signal timing plans for the signalized arterials. The procedures calculating delay and stops are based on Michalopoulos's analytical model derived from shock wave theory. The delay-offset relationship predicted from the algorithm produced consistent results with the delays venerated by TRANSYT-7F. From performance test, the delays estimated using the proposed a1gorithm are shown to be sensitive to the quality of progression as well as to traffic demand, link length, and turning flow ratio from upstream signal.

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A Dynamic Rain Attenuation Model for Adaptive Satellite Communication Systems (적응형 위성통신 시스템 설계를 위한 동적 강우 감쇠 모델)

  • Zhang, Meixiang;Kim, Soo-Young;Pack, Jeong-Ki
    • Journal of Satellite, Information and Communications
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    • v.6 no.1
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    • pp.12-18
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    • 2011
  • Signal fading due to rain is one of the most significant factors degrading link quality in satellite communication systems. Adaptive transmission is considered to be the most efficient means to countermeasure the rain attenuation. In order to develop and design a good adaptive transmission system, we need a dynamic rain attenuation model which can synthesize time series of rain attenuation. In this paper, we present a modeling technique for dynamic rain attenuation using a Markov process. We derive statistical fading properties of the rain attenuation data measured in second time interval and define four states in the Markov process. We synthesize the rain attenuation data using the 4-state Markov process, and compare statistical properties of the simulated data to those of the measured data.