• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.5
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• pp.21-26
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• 2012

Intra-session network coding has been proposed to improve throughput by simplifying scheduling of multi-hop wireless network and efficiency of packet transmission. Multi-rate transmission has been used in multihop wireless networks. An opportunistic routing with multirate shows throughput improvement compared with single rate. In this paper, we propose a method of throughput improvement in multi-hop wireless network by using multi-rate and intra-session network coding. We suggest a method to select an local optimal transmission rate at each node. The maximum throughput is evaluated by using linear programming (LP). To solve the LP, we use MATLAB and lp_solve IDE program. The performance evaluation results show that end-to-end throughput is improved by using multirate and intra-session network coding can achieve better throughput than opportunistic routing.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.19-28
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• 2022

In this paper, we propose the Detector Scheduler which determines the best tracking-by-detection (TBD) mechanism to perform real-time high-accurate multi-object tracking (MOT). The Detector Scheduler determines whether to run a detector by measuring the dissimilarity of features between different frames. Furthermore, we propose a self-supervision method to learn the Detector Scheduler with tracking results since it is difficult to generate ground truth (GT) for learning the Detector Scheduler. Our proposed self-supervision method generates pseudo labels on whether to run a detector when the dissimilarity of the object cardinality or appearance between frames increases. To this end, we propose the Detector Scheduling Loss to learn the Detector Scheduler. As a result, our proposed method achieves real-time high-accurate multi-object tracking by boosting the overall tracking speed while keeping the tracking accuracy at most.

• Journal of Construction Engineering and Project Management
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• v.7 no.3
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• pp.1-14
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• 2017

Delay claim should actually be supported by a set of proper information so that the contractors could prove their validity. The so-called information should be able to clarify the relationship between delay events and how they impact on the whole project. Therefore, exploiting an integrated system by people who are involved in construction business would certainly prove helpful. In the present study, delay analysis methods have been investigated along with selecting a relatively comprehensive method which has been modified, and eventually, a novel model and its required modules have been proposed for evaluating delay claims. The suggested integrated model is formed to identify delayed events, to classify delays, to measure the impacts of delays on the project scheduling, and finally to estimate the damages which were caused by those so-called delays. A decision support system (DSS) model which is related to the integrated system is actually extracted from Iran's general contract conditions, that is, 4311 magazine (equivalent to red FIDIC book). It is then programmed and coded by C# program. This DSS model can be used as an input of Easy Plan program. In addition, at the end of this research, the coded DSS has been used along with the so-called program so that a modified and developed model could be generated.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.385-395
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• 1999

Video-On-demand system provides electronic video rental services from remote video servers on a broadband communication networks. When we assume some situation that serve the same video stream by batching, each time single video stream became available at server-end side, we face the problem that what video stream to be scheduled at what time instant. Hence, in order to manage the resource bandwidth which is different at each stream, the policy of channel allocation became important factor. In this work, we proposed three type of scheduling policies with queueing, as are cumulative Waiting Time(CWT), Mean Waiting Time(MWT) and Predictable Popular Factor(PPF). While CWT policy is good for popular video, MWT policy was good for non-popular video. Also, we know that PPT policy has some fairness for average wait time and reneging rate of user requests.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.16-24
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• 2010

High Speed Uplink Packet Access(HSUPA) is a WCDMA Release 6 technology which corresponds to High Speed Downlink Packet Access(HSDPA). Node B Supports fast scheduling, Hybrid ARQ(HARQ), short Transmission Time Interval(TTI) for high rate uplink packet data. It is very important to detect Iub congestion to improve end user's Quality of Service(QoS). This paper proposes Node B Congestion Detection(BCD) mechanism and suggests to use the hybrid of Transport Network Layer(TNL) congestion detection and BCD. It is shown that HSUPA user throughput performance can be improved by the proposed method even with small Iub bandwidth.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1639-1644
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• 2016

In this paper, we consider the performance improvement that can be obtained with interference alignment (IA) technique applied to 802.11ac based multi-BSS WiFi service. To this end, we developed a system simulator consisting of a link-level PHY simulator, based on 802.11ac specification, and multi-BSS proportional-fair scheduler. Specifically, assuming perfect channel side information and synchronization of signals from multiple APs, we used a SLNR based interference alignment algorithm proposed in [13] and compared its performance with that of multiuser beamforming based time-sharing system. The performance was evaluated in terms of average throughput per BSS and 5% worst user throughput. The results show that 70 to 100% throughput gain can be obtained in this ideal scenario.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.2
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• pp.132-143
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• 2011

This paper deals with a coal supply planning problem for power plants. We propose a mathematical optimization model to make decisions for coal pile sections, movement of reclaimers, and operation time of conveyor belts. The objective of the proposed model is to minimize the total operation time of conveyor belts and total movement time of reclaimers. The algorithm firstly selects a pile section by considering both the location of reclaimers and the stock amount on that pile section. And then the shortest path from the selected pile section has to be put into the operation schedule and check whether the total operation time is satisfied. Then finally the new schedule is updated. To this end, we have tested the proposed algorithm comparing with the general standard optimization package for the simplified problem SCSPP. From the numerous test runs for comparing with the existing coal supply scheduling methods, We see that the proposed model may improve the coal supply operation by reducing significant coal supply costs.

• Journal of Digital Contents Society
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• v.7 no.3
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• pp.207-210
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• 2006

A synchronized multimedia presentation consists of a collection of objects, with each object having one or more rendering intervals within the presentation timeline. These intervals specify the objects' start times and end times relative to the presentation timeline. In this paper we consider the problem of streaming a multimedia presentation from a server to a client over a bandwith-limited communication network. We suppose that each of the static objects is layered-encoded. For a given maximum delay, we consider the problem of finding the optimal number of quality of the presentation. We devise efficient algorithms for determining an optimal policy for several criteria. We also consider the problem of gradual rendering of objects after their start times.

• Journal of Construction Engineering and Project Management
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• v.4 no.4
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• pp.47-59
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• 2014

Client organization inadequate project planning before awarding the contract and insufficient monitoring and control system among the parties involved create severe problems. Ultimately, large-scale projects go beyond the expected cost and time control limits. This paper discusses the major issues involved with a large-scale Hydropower Project in Pakistan Public Sector environment. The latest approved Baseline Plan of project was reviewed and analyzed using Variance Analysis and Trend Analysis techniques in Primavera project management software to assess the efforts made of the parties involved. It was found that Project is 202% Cost overrun and 25% time delays from original contract award. After analysis of baseline plan and quantification of various variance issues in impacted activities, the questionnaire survey was conducted to identify the impact of causative factors. There were almost 17 most significant causative factors identified among 60 identified factors and responsibilities are assigned accordingly. At the end recommendations are made for strategic decisions as lessons learned during project evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.312-321
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• 2018

The Korean DR market proposes suppression of peak demand under reliability crisis caused a natural disaster or unexpected power plant accidents as well as saving power plant construction costs and expanding amount of reserve as utility's perspective. End-user is notified a DR event signal DR execution before one hour, and executes DR based on requested amount of load reduction. This paper proposes a DR energy management algorithm that can be scheduled the optimal operations of chiller system and ESS in the next day considering the TOU tariff and DR scheme. In this DR algorithm is divided into two scheduling's; day-ahead operation scheduling with temperature forecasting error and operation rescheduling on DR operation. In day-ahead operation scheduling, the operations of DR resources are scheduled based on the finite number of ambient temperature scenarios, which have been generated based on the historical ambient temperature data. As well as, the uncertainties in DR event including requested amount of load reduction and specified DR duration are also considered as scenarios. Also, operation rescheduling on DR operation day is proposed to ensure thermal comfort and the benefit of a COB owner. The proposed method minimizes the expected energy cost by a mixed integer linear programming (MILP).