• Asian-Australasian Journal of Animal Sciences
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• 제22권12호
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• pp.1609-1613
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• 2009

The objective of this study was to estimate genetic parameters for racing performance traits of thoroughbredracehorses, using a total of 58,124 racing records of 4,200 horses at Gwacheon Racing Park collected from January 2002 to December 2006. This study measured start one furlong time, last three and last one furlong times, and the resulting furlong time averages were 14.2 seconds, 39.9 seconds and 13.9 seconds, respectively. Furlong time means a split time measured based on a 1/8-mile (or approximately 201 m) distance and finished time means total racing time measured from start position to finish line. In the shortest distance races of 1,000 m, the average last three and last one furlong time was fastest at 38.7 seconds and 13.6 seconds, respectively. The correlation between finished time and start one furlong time decreased as the race distance increased, and the same trend was recognized from the correlation between finished time and last three furlong time. In short distance races of 1,400 m or less, the starting ability was found to be an important trait. The average speed was highest at 56 km/h for a 1,000 m race and lowest at 53.2 km/h for a 1,700 m race. Heritabilities of the start one furlong time, the last three and last one furlong time were estimated to be 0.337, 0.245 and 0.210, respectively; and repeatabilities for them were 0.452, 0.353 and 0.309, respectively. Phenotypic and genetic correlations between the start and the last one furlong time were negative at -0.141 and -0.155, respectively.

• 한국ITS학회 논문지
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• 제21권5호
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• pp.183-196
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• 2022

국내의 경우 대중교통 최소서비스 수준 분석을 통해 대중교통 접근성을 평가하고 있으나 이는 운영자 측면의 평가로 이용자 측면의 대중교통 접근성 분석은 이루어지지 않고 있다. 이에 본 연구에서는 알뜰교통카드 데이터를 이용하여 이용자의 대중교통 접근성을 분석한 결과 법정동보다 법정리의 접근시간 및 거리가 크며, 대중교통 접근성이 낮은 유형을 분류하여 분석한 결과 전체 평균 접근 시간에 비해 유형 1은 95%, 유형 2는 64% 더 크게 나타났다. 이러한 대중교통 접근성 문제 해결을 위해 델파이 조사를 통한 실시간 수요대응 자율주행 대중교통차량의 효율적인 도입 방안을 제시하고자 하였다. 델파이 조사 결과 기능은 환승연계 및 D2D, 서비스는 예약 및 정보제공서비스, 노선 운영 방식은 준동적 및 동적 운영, 접근거리는 300m, 노선 운행 거리는 10km, 정시성은 5분 이내와 같이 9개 항목에 대해 전문가들의 의견이 일치하였다.

• IEIE Transactions on Smart Processing and Computing
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• 제1권1호
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• pp.27-33
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• 2012

The Ethernet Passive Optical Network (EPON) has been considered to be one of the most promising solutions for the implementation of the Fiber To The Home (FTTH) technology designed to ameliorate the "last mile" bandwidth bottleneck. In the EPON network, an efficient and fair bandwidth allocation is a very important issue, since multiple optical network units (ONUs) share a common upstream channel for packet transmission. To increase bandwidth utilization, an EPON system must provide a way to adaptively allocate the upstream bandwidth among multiple ONUs in accordance to their bandwidth demands and requirements. We present a new hybrid method that satisfies these requirements. The advantage of our method comes from the consideration of application-specific bandwidth allocation and the minimization of the idle bandwidth. Our simulation results show that our proposed method outperforms existing dynamic bandwidth allocation methods in terms of bandwidth utilization.

• Journal of information and communication convergence engineering
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• 제18권2호
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• pp.100-105
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• 2020

With the advent of the 5G era, the rapid growth in demand for mobile content services has increased the need for additional backhaul investment. To meet this demand, employing a content delivery network (CDN) and optical access solution near the last mile has become essential for the configuration of 5G networks. In this paper, a cache-enabled architecture using the passive optical network (PON) is presented to serve video on demand (VoD) for users. For efficient use of mobile backhaul, I propose a request deduplication scheme (RDS) that can provide all the requested services missed in cache with minimum bandwidth by eliminating duplicate requests for movies within tolerable range of the quality of service (QoS). The performance of the proposed architecture is compared with and without RDS in terms of the number of requests arriving at the origin server (OS), hit ratio, and improvement ratio according to user requests and cache sizes.

• 전자통신동향분석
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• 제25권2호
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• pp.57-67
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• 2010

최근에 3.5G, 4G 이동통신, WiMax 등 다양한 고속 무선 데이터 서비스의 발달이 급속도로 진행됨에 따라 기지국을 위한 무선 백홀의 전송속도가 현재 보다 급격히 높아질것으로 예상되며, 광 백본망에 연결되지 않은 빌딩들을 위한 광통신망과 빌딩간 'Last Mile' 구간에 대한 경제적인 통신망 확보가 요구되고 있다. 본 고에서는 경제적으로 Gbps급 광 백본망과 가입자를 연결하거나, Gbps급 사설통신망 및 백홀에 이용할 수 있는 E-band 이용 Multi-Gbps급 고정 점대점 통신 시스템과 송수신기 핵심 구성 부품의 기술 개발 동향을 소개하고자 한다.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2012년도 제45차 동계학술발표논문집 20권1호
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• pp.105-108
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• 2012

Wireless mesh networks are considered a promising solution to last mile broadband. The unique characteristics of WMN impose unique requirements on designing routing protocols and metrics for WMN. However, existing routing schemes that are designed for single-channel multi-hop wireless networks may lead to inefficient routing paths in multichannel. This paper focuses on the routing problem for multi-radio multichannel WMNs. We list the challenges in designing routing algorithms for multi-radio multichannel WMNs. Then we examine the requirements and considerations for designing routing metrics according to the characteristics of multi-radio multichannel WMNs. Finally we survey and investigate the existing routing metrics in terms of their ability to satisfy these requirements.

• ETRI Journal
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• 제40권1호
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• pp.89-100
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• 2018

Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use-case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof-of-concept wireless backhaul solution developed within the EU-KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over-the-air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.443-450
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• 2021

The study is devoted to the formation of a economic principles cargo delivery management in global supply chains. Mathematical model of delivering special categories of goods by road is a key element of these principles. The article analyzes the existing studies on solving the problem of cargo delivery in various aspects. It was noted that the greatest attention is paid to legal regulation, last mile delivery, optimization of routes and delivery schemes, information support, technological innovations, cluster routing, etc. In the developed mathematical model a minimum of total costs of forming loading units and freight shipments was defined as the criterion of optimality of organizing delivery by motor transport. The authors propose the creation of logistics clusters allowing the integration of urban transport flows and global supply chains.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.1-9
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• 2020

Global e-commerce and delivery companies are actively pursuing last-mile delivery service using drones, and various delivery schedule planning studies have been conducted. In this study, separate individual route networks were constructed to reflect drone route constraints such as prohibited airspace and truck route constraints such as rivers, which previous studies did not incorporate. The A* algorithm was used to calculate the shortest path distance matrix between the starting point and destinations. In addition, we proposed an optimal delivery schedule plan using genetic algorithms and applied it to compare the efficiency with that of vehicle-only delivery.

• ETRI Journal
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• 제45권2호
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• pp.329-337
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• 2023

For safe last-mile autonomous robot delivery services in complex environments, rapid and accurate collision prediction and detection is vital. This study proposes a suitable neural network model that relies on multiple navigation sensors. A light detection and ranging technique is used to measure the relative distances to potential collision obstacles along the robot's path of motion, and an accelerometer is used to detect impacts. The proposed method tightly couples relative distance and acceleration time-series data in a complementary fashion to minimize errors. A long short-term memory, fully connected layer, and SoftMax function are integrated to train and classify the rapidly changing collision countermeasure state during robot motion. Simulation results show that the proposed method effectively performs collision prediction and detection for various obstacles.