• 한국산학기술학회논문지
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• 제15권6호
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• pp.3997-4001
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• 2014

본 연구는 경북지역에 산재한 사용종료 비위생 매립 부지의 특성을 토대로 효율적인 부지 활용 방안 제시를 목적으로 하였다. 연구 대상 매립 부지의 활용성에 영향을 주는 인자를 선정하여 매립 부지의 유형을 분류함으로써 체계적인 활용방안 선택의 기초 자료를 제공하였다. 매립 부지의 활용 인자로는 부지의 면적, 도로 이격 거리, 마을 이격 거리를 분석하였으며 통계 분석을 통하여 대상 매립 부지의 유형을 결정짓는 주요 인자는 부지의 면적임을 알 수 있었다. 이러한 결과를 토대로 매립 부지의 특성에 알맞은 활용 방안 결정 지침을 제시하였다.

• Journal of Communications and Networks
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• 제12권2호
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• pp.103-113
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• 2010

In this paper, a tradeoff between the total energy consumption-per-bit and the end-to-end rate under spatial reuse in wireless multi-hop network is developed and analyzed. The end-to-end rate of the network is the number of information bits transmitted (end-to-end) per channel use by any node in the network that is forwarding the data. In order to increase the bandwidth efficiency, spatial reuse is considered whereby simultaneous relay transmissions are allowed provided there is a minimum separation between such transmitters. The total energy consumption-per-bit includes the energy transmitted and the energy consumed by the receiver to process (demodulate and decoder) the received signal. The total energy consumption-per-bit is normalized by the distance between a source-destination pair in order to be consistent with a direct (single-hop) communication network. Lower bounds on this energy-bandwidth tradeoff are analyzed using convex optimization methods. For a given location of relays, it is shown that the total energy consumption-per-bit is minimized by optimally selecting the end-to-end rate. It is also demonstrated that spatial reuse can improve the bandwidth efficiency for a given total energy consumption-per-bit. However, at the rate that minimizes the total energy consumption-per-bit, spatial reuse does not provide lower energy consumption-per-bit compared to the case without spatial reuse. This is because spatial reuse requires more receiver energy consumption at a given end-to-end rate. Such degraded energy efficiency can be compensated by varying the minimum separation of hops between simultaneous transmitters. In the case of equi-spaced relays, analytical results for the energy-bandwidth tradeoff are provided and it is shown that the minimum energy consumption-per-bit decreases linearly with the end-to-end distance.

• 한국멀티미디어학회논문지
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• 제16권5호
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• pp.601-609
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• 2013

One of the most serious factors constraining the next generation cellular mobile consumer communication systems will be the severe co-channel interference experienced at the cell edge. Such a capacity-degrading impairment combined with the limited available spectrum resource makes it essential to develop more spectrally efficient solutions to enhance the system performance and enrich the mobile user's application services. This paper proposes a unique hybrid method of frequency hopping (FH) and subcarrier-reuse-partitioning that can maximize the system capacity by efficiently utilizing the available spectrum while at the same time reduce the co-channel interference effect. The main feature of the proposed method is that it applies an optimal combination of different frequency reuse factors (FRF) and FH-subcarrier allocation patterns into the partitioned cell regions. From the simulation results, it is shown that the proposed method can achieve the optimum number of subcarrier subsets according to the frequency-reuse distance and results in better performance than the fixed FRF methods, for a given partitioning arrangement. The results are presented in the context of both blocking probability and BER performances. It will also be shown how the proposed scheme is well suited to FH-OFDMA based cellular systems aiming at low co-channel interference performance and optimized number of subcarriers.

• Journal of Communications and Networks
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• 제8권1호
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• pp.13-20
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• 2006

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.

• 인터넷정보학회논문지
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• 제22권5호
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• pp.1-8
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• 2021

Small-cells in heterogeneous networks are one of the important technologies to increase the coverage and capacity in 5G cellular networks. However, due to the randomly arranged small-cells, co-tier and cross-tier interference increase, deteriorating the system performance of the network. In order to manage the interference, some channel management methods use fractional frequency reuse(FFR) that divides the cell coverage into the inner region(IR) and outer region(OR) based on the distance from the macro base station(MBS). However, since it is impossible to properly measure the distance in the method with FFR, we propose a new interference aware FFR(IA-FFR) method to enhance the system performance. That is, the proposed IA-FFR method divides the MUEs and SBSs into the IR and OR groups based on the signal to interference plus noise ratio(SINR) of macro user equipments(MUEs) and received signals strength of small-cell base stations(SBSs) from the MBS, respectively, and then dynamically assigns subchannels to MUEs and small-cell user equipments. As a result, the proposed IA-FFR method outperforms other methods in terms of the system capacity and outage probability.

• Current Optics and Photonics
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• 제8권4호
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• pp.345-354
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• 2024

The bit walk-off effect caused by fiber dispersion and carrier reuse in the base station (BS) are two key problems in radio-over-fiber (ROF) systems. In this paper, a novel frequency-octupling ROF system based on the Mach-Zehnder modulator (MZM) is proposed, which can overcome the bit walk-off effect and realize carrier reuse by inserting pilot signals. Theoretical analysis and simulation verification of the system are carried out. Under the condition of a Q factor greater than 6, the optical fiber transmission distance of the upper and lower links is more than 290 km and 80 km, respectively. The influence of the main device parameters of the system on the Q factor is analyzed when they deviate from their designed values. The system designed in this paper can not only effectively overcome the bit walk-off effect, but also solve the problem of downlink performance degradation and the limitation of tunability caused by conventional carrier reuse in ROF. The system can greatly increase the transmission distance and improve the performance of the system and has an important application prospect in ROF.

• 통합자연과학논문집
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• 제13권1호
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• pp.1-7
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• 2020

This paper proposes a novel fractional frequency reuse(FFR) based on dynamic user distribution. In the FFR, a macro cell is divided into two regions, i.e., the inner region(IR) and outer region(OR). The criterion for dividing the IR and OR is the distance ratio of the radius. However, these distance-based criteria are uncertain in measuring user performance. This is because there are various attenuation phenomena such as shadowing and wall penetration as well as path loss. Therefore, we propose a novel FFR based on dynamic user classification with signal to interference plus noise ratio(SINR) of macro users and classify the FFR into two regions newly. Simulation results show that the proposed scheme has better performance than the conventional FFR in terms of SINR and throughput of macro cell users.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2020년도 제61차 동계학술대회논문집 28권1호
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• pp.1-2
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• 2020

응용프로그램의 응답성을 향상시키기 위해서는 저장장치 시스템의 데이터 처리 능력이 중요하다. 한편, 차세대 메모리(NVDIMM)는 DRAM과 SSD 중간 정도의 성능 특성과 저장 용량을 갖는다. NVDIMM을 저장장치의 캐시로 사용함으로써 메모리와 저장장치의 격차는 많이 줄게 된다. 본 논문에서는 경량의 재사용 거리 측정 기법을 이용하여 효율적으로 디스크를 캐싱하는 기법을 제안한다. 제안 기법은 경량의 재사용 거리 측정 기법을 바탕으로 계산된 CFD(Computational Fluid Dynamics)값에 따라 디스크 캐시에 해당 데이터 적재 여부를 결정한다. 결과적으로 제안 기법을 적용한 디스크 캐시를 운용함에 따라 캐시의 히트율을 향상시켰다.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2001년도 가을 학술발표논문집 Vol.28 No.2 (3)
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• pp.160-162
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• 2001

Cyclic-Reservation Multiple-Access(CRMA) is an access scheme for high-speed local and metropolitan area networks based on folded-bus or dual-bus configurations. CRMA provides high throughput and fairness independent of the network speed or distance. This paper describes a simulation-based quantitative analysis of the performance gains obtained by introducing slot reuse in CRMA. Generally, a longer cycle length means a longer access delay and a lower throughput. There-fore, it is desirable to develop a scheme such that the cycle length is the shortest. In this paper, we will study the problem of reducing the total number of empty slots generated within every cycle. However, it has been shown that the problem is NP-complete under the constraint that all empty slots used by a station in a cycle are required to be consecutive. We present the algorithm that improves previous novel approach by using previous node information. We compare our slots reuse scheme with several slot reuse algorithms such as region scheme (FMR), address schemes, novel approach in terms of the following two important performance criteria: average cycle length and average slot utilization ratio. As compared with the one proposed in novel algorithm, the new scheme makes the cycle length much shorter. Besides, the resulting slot utilization and the access delay are better than those of the other two schemes.

• 한국컴퓨터정보학회논문지
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• 제27권3호
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• pp.183-199
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• 2022

스마트폰 콘텐츠 소비가 늘면서 중국 짧은 동영상(short clip) 시장이 급성장하고 있다. 이에 짧은 동영상 플랫폼인 TikTok이 큰 비즈니스 성공을 거두었다. 그러나 Tiktok플랫폼의 성공요인에 대한 고객중심적 연구는 많지 않다. 이를 위해 본 연구는 실증조사를 통해 Tiktok플랫폼의 소셜네트워크, TikTok플랫폼에 대한 애착, 사용자 참여, 심리적 거리감, 사회적 정체성 및 재사용의도 간의 관계를 검증하는 연구목적을 가진다. 2021년 10월 중국 내 TikTok플랫폼을 사용하는 소비자를 대상으로 설문조사를 실시하였다. 연구 결과 첫째, 소셜네트워크 특성은 사용자 참여와 애착에 유의한 영향을 미쳤다. 둘째, 사용자 참여는 사용자 애착에 유의한 영향을 미쳤다. 셋째, 사용자 애착과 사용자 참여 모두 재사용 의도에 유의한 영향을 미쳤다. 넷째, 심리적 거리감은 소셜네트워크 특성과 사용자 애착 사이의 관계를 부분 조절하는 역할을 하였다. 다섯째, 사회적 정체성은 소셜네트워크 특성과 사용자 참여 사이의 관계를 부분 조절하는 역할을 하였다. 이 연구 결과는 TikTok플랫폼 연구에 관한 이론적이고 실무적인 시사점을 제공할 것으로 기대된다.