• Title/Summary/Keyword: Flow network model

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Design for Carbon Neutral Arboretum in Gwangju Metropolitan City (광주광역시 탄소중립 수목원 설계)

  • Kim, Hoon Hee
    • KIEAE Journal
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    • v.9 no.3
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    • pp.61-68
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    • 2009
  • Gwangju Metropolitan Government & Ministry of Environment have signed a model city in response to Climate Change agreement. The agreement calls for Gwangju to cut greenhouse gas emissions 10% below 2005 levels by 2015. Gwangju has seen this agreement as an opportunity to cut pollution and conserve the environment as well as to reinvigorate local economy. According to policy of Gwangju, Gwangju held design competition for Gwangju City Arboretum on march, 2009. The purpose of design competition was to give a wide publicity to Gwangju as Hub City of Asian Culture and construct carbon-neutral arboretum in accordance with the policy of 'Low-Carbon and Green Growth'. First of all, a design concept of arboretum is 'winding, round, overlay 'to reflect the landscape of Nam-do which is surrounded by mountains and river flows through the village. Second, the arboretum has five different places with these themes - Forest of Festivals, Health, Nature, Nostalgia, Education and Future. Each place has a symbolic theme park and different flow planning respectively. Third, the most critical point is that the arboretum is a carbon-neutral park. Gwangju arboretum will soon be developed in metropolitan sanitary landfill and constructed as the O2 arboretum based on low carbon strategy. Fourth, the O2 arboretum suggests specialized issue : 'Energy Saving', 'Recycling System', 'Green Network', 'Water System(rainwater maintenance and wetland development)'. Besides, main buildings(greenhouse, visitor center, Nam-do experience exhibition hall, and forest museum) is designed in consideration of harmony with topography character, surroundings. Also, planting will be a multilayer plant based on native landscape trees in consideration of function and the growth characteristics.

The Authentication Model which Utilized Tokenless OTP (Tokenless OTP를 활용한 인증 모델)

  • Kim, Ki-Hwan;Park, Dea-Woo
    • KSCI Review
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    • v.14 no.2
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    • pp.205-214
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    • 2006
  • Is need Remote Access through internet for business of Ubiquitous Computing age, and apply OTP for confidentiality about inputed ID and Password, network security of integrity. Current OTP must be possessing hardware or Token, and there is limitation in security. Install a Snooping tool to OTP network in this treatise, and because using Cain, enforce ARP Cache Poisoning attack and confirm limitation by Snooping about user password. Wish to propose new system that can apply Tokenless OTP by new security way, and secure confidentiality and integrity. Do test for access control inflecting Tokenless OTP at Remote Access from outside. and could worm and do interface control with certification system in hundred. Even if encounter hacking at certification process, thing that connection is impossible without pin number that only user knows confirmed. Because becoming defense about outward flow and misuse and hacking of password when apply this result Tokenless OTP, solidify security, and evaluated by security system that heighten safety.

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Energy Analysis in CO2 Membrane Separation Process via Heat Integration (열통합 기법을 통한 이산화탄소 막 분리공정 에너지 해석)

  • Kim, Seong Hun;Kim, Tae Yong;Kim, Beom Seok;Cho, Hyun-Jun;Yeo, Yeong Koo
    • Plant Journal
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    • v.12 no.2
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    • pp.24-30
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    • 2016
  • The membrane separation processes have received attention due to advantages such as compactness, modularity, ease of installation, flexibility of operation, lower capital cost and lower energy consumption. In this study, we evaluated accuracy of cross-flow, co-current and counter-current models. With the most accurate model, we identified the operating conditions of the two-stage membrane separation and examined the effects of permeance and selectivity of the membrane by simulation. Futhermore, power requirements and operating cost savings due to the introduction of the heat exchanger were investigated by applying heat exchanger network synthesis technique in the two-stage membrane separation using vapor sweep.

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A Mathematical Approach to Allocate the Contributions by Applying UPFCs to Transmission System Usage

  • Sedaghati, Alireza
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.158-163
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    • 2005
  • Competitive electricity markets necessitate equitable methods for allocating transmission usage in order to set transmission usage charges and congestion charges in an unbiased and an open-accessed basis. So in competitive markets it is usually necessary to trace the contribution of each participant to line usage, congestion charges and transmission losses, and then to calculate charges based on these contributions. A UPFC offers flexible power system control, and has the powerful advantage of providing, simultaneously and independently, real-time control of voltage, impedance and phase angle, which are the basic power system parameters on which sys-tem performance depends. Therefore, UPFC can be used efficiently and flexibly to optimize line utilization and increase system capability and to enhance transmission stability and dampen system oscillations. In this paper, a mathematical approach to allocate the contributions of system users and UPFCs to transmission system usage is presented. The paper uses a dc-based load flow modeling of UPFC-inserted transmission lines in which the injection model of the UPFC is used. The relationships presented in the paper showed modified distribution factors that modeled impact of utilizing UPFCs on line flows and system usage. The derived relationships show how bus voltage angles are attributed to each of changes in generation, injections of UPFC, and changes in admittance matrix caused by inserting UPFCs in lines. The relationships derived are applied to two test systems. The results illustrate how transmission usage would be affected when UPFC is utilized. The relationships derived can be adopted for the purpose of allocating usage and payments to users of transmission network and owners of UPFCs used in the network. The relationships can be modified or extended for other control devices.

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A Study on the Analysis of $CO_2$ Concentration Variation According to the Indoor Space Condition Changes (다양한 실내 환경에서의 $CO_2$ 농도 변화 분석 연구)

  • Ahn, Gwang-Hoon;Kwon, Jong-Won;Kim, Gyu-Sik;Kim, Hie-Sik
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.347-349
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    • 2009
  • Air quality of indoor space environment is affected by various pollutants like as particles and chemical stuffs. The indoor air pollution affects directly the human respiration organs to cause consequently unpleasant mental status. The $CO_2$ concentration level is one of the harmful components of air pollutants. Major factor to increase the $CO_2$ concentration level is the people's breath amount in indoor. The car exhaust gas diffused from the around road also has strong affect on $CO_2$ concentration. There are some other reasons to affect the $CO_2$ concentration change, such as, real-time change of the population movement, closeness to the indoor air flow inlet window and changes in road car traffic amount. A remote monitoring system to measure environmental indoor air pollution concerning on the $CO_2$ concentration was studied and installed realized set-up model. Zigbee network configuration was applied for this system and the $CO_2$ concentration data were collected through USN network. A software program was developed to assure systematic analysis and to display real-time data on web pages. For the experimental test various condition was set up, like as, window opening, stopping air condition operation and adjusting fan heater work, etc. The analysis result showed the relation of various environmental conditions to $CO_2$ concentration changes. The causes to increase $CO_2$ concentration were experimentally defined as windows closing, the stopping air condition system, fan heater operation. To keep the $CO_2$ concentration under the legally required ppm level in public access indoor space, the developed remote measurement system will be usefully applied.

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Dynamic Resource Reservation for Ultra-low Latency IoT Air-Interface Slice

  • Sun, Guolin;Wang, Guohui;Addo, Prince Clement;Liu, Guisong;Jiang, Wei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.7
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    • pp.3309-3328
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    • 2017
  • The application of Internet of Things (IoT) in the next generation cellular networks imposes a new characteristic on the data traffic, where a massive number of small packets need to be transmitted. In addition, some emerging IoT-based emergency services require a real-time data delivery within a few milliseconds, referring to as ultra-low latency transmission. However, current techniques cannot provide such a low latency in combination with a mice-flow traffic. In this paper, we propose a dynamic resource reservation schema based on an air-interface slicing scheme in the context of a massive number of sensors with emergency flows. The proposed schema can achieve an air-interface latency of a few milliseconds by means of allowing emergency flows to be transported through a dedicated radio connection with guaranteed network resources. In order to schedule the delay-sensitive flows immediately, dynamic resource updating, silence-probability based collision avoidance, and window-based re-transmission are introduced to combine with the frame-slotted Aloha protocol. To evaluate performance of the proposed schema, a probabilistic model is provided to derive the analytical results, which are compared with the numerical results from Monte-Carlo simulations.

Resilient Routing Protocol Scheme for 6LoWPAN (6LoWPAN에서 회복력 있는 라우팅 프로토콜 기법)

  • Woo, Yeon Kyung;Park, Jong Tae
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.11
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    • pp.141-149
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    • 2013
  • IETF 6LoWPAN standard technique has been studied in IoT environment to support the IPv6 packet communication. 6LoWPAN protocol for transmission of packets mainly in the AODV routing protocol and a variety of extended techniques have been investigated. In particular, consisting of nodes with limited resources in a network error occurs when the 6LoWPAN reliable data transfer and fast routing method is needed. To this end, in this paper, we propose resilient routing protocol and extension of IETF LOAD algorithm, for optimal recovery path, More specifically, the optimal recovery path setup algorithm, signal flow, and detailed protocols for the verification of the reliability of packet transmission mathematical model is presented. The proposed protocol techniques to analyze the performance of the NS-3 performance through the simulation results that is end-to-end delay, throughput, packet delivery fraction and control packet overhead demonstrated excellence in comparison with existing LOAD.

The Authentication Model which Utilized Tokenless OTP (Tokenless OTP를 활용한 인증 모델)

  • Kim, Ki-Hwan;Park, Dea-Woo
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.1 s.45
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    • pp.107-116
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    • 2007
  • Is need Remote Access through internet for business of Ubiquitous Computing age, and apply OTP for confidentiality about inputed ID and Password, network security of integrity. Current OTP must be possessing hardware of Token, and there is limitation in security. Install a Snooping tool to OTP network in this treatise, and because using Cain, enforce ARP Cache poisoning attack and confirm limitation by Snooping about user password. Wish to propose new system that can apply Tokenless OTP by new security way, and secure confidentiality and integrity. Do test for access control inflecting Tokenless OTP at Remote Access from outside, and could worm and do interface control with certification system in hundred. Even if encounter hacking at certification process, thing that connection is impossible without pin number that only user knows confirmed. Because becoming defense about outward flow and misuse and hacking of password when apply this result Tokenless OTP, solidify security, and evaluated by security system that heighten safety.

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Trend Analysis of Korea Papers in the Fields of 'Artificial Intelligence', 'Machine Learning' and 'Deep Learning' ('인공지능', '기계학습', '딥 러닝' 분야의 국내 논문 동향 분석)

  • Park, Hong-Jin
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.4
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    • pp.283-292
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    • 2020
  • Artificial intelligence, which is one of the representative images of the 4th industrial revolution, has been highly recognized since 2016. This paper analyzed domestic paper trends for 'Artificial Intelligence', 'Machine Learning', and 'Deep Learning' among the domestic papers provided by the Korea Academic Education and Information Service. There are approximately 10,000 searched papers, and word count analysis, topic modeling and semantic network is used to analyze paper's trends. As a result of analyzing the extracted papers, compared to 2015, in 2016, it increased 600% in the field of artificial intelligence, 176% in machine learning, and 316% in the field of deep learning. In machine learning, a support vector machine model has been studied, and in deep learning, convolutional neural networks using TensorFlow are widely used in deep learning. This paper can provide help in setting future research directions in the fields of 'artificial intelligence', 'machine learning', and 'deep learning'.

Design and Implementation of a Simulator for the Performance Simulation of a Large-Scale Network Using OPNET (OPNET을 이용한 대규모 망 성능 모의실험을 위한 시뮬레이터 설계 및 구현)

  • Park, Jeong-Sook;Jeon, Yong-Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.3B
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    • pp.274-287
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    • 2009
  • In the Internet environment in which best-effort services are provided, we need to guarantee end-to-end performance rather than hop performance to provide services with a variety of QoS(Quality of Service) requirements. The end-to-end performance is affected by many factors along the path of traffic flow. Most existing simulation studies are concentrated on a single node or a few nodes. We need much different approach considering the simulation execution time to simulate a large-scale network. In this paper, we derive requirements and present methodologies for the implementation of the simulator to simulate it. Then, we design and implement our simulator using OPNET. Performance evaluation is carried out using the simulator for large-scale KII (National Information Infrastructure in Korea). We use a self-similar traffic model and present some results on the end-to-end performance metric for the networks.