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A Study on QoS Performance Based on CBQ Using Real-time Transport Protocol (RTP를 이용한 CBQ기반의 QoS 성능에 관한 연구)

  • 하미숙;박승섭
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.43-48
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    • 2004
  • RTP that is proposed supplement of real-time services on internet environment, as Real-time Transport Protocol, is the protocol that for the purpose of sending data of stream type. RTP and RTCP(Real-time Transport Control Protocol) basically work at the same time, RTCP serves with state information of network at present. RTP has important properties of a transport protocol that runs on end-to-end systems and provides demultiplexing. It also offer reliability and protocol-defined flow/congestion control that transport protocol like TCP can not provides. In this paper, we look around concept and construction of Differentiated sen1ice tint run on RTP and by setting parameters of packet transfer method be used CBQ(Class-Based Queuing) for packet transfer on Differentiated service, each service queue controls properly through packet scheduling method, such as WRR(Weighted Round Robin) and PRR(Packet-by-packet Round Robin) all service classes do not experience the starvation and confirm the performance through computer simulation to achieve fairly scheduling.

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Bandwidth-Award Bus Arbitration Method (점유율을 고려한 버스중재 방식)

  • Choi, Hang-Jin;Lee, Kook-Pyo;Yoon, Yung-Sup
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.5
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    • pp.80-86
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    • 2010
  • The conventional bus system architecture consists of masters, slaves, arbiter, decoder and so on in shared bus. As several masters can't use a bus concurrently, arbiter plays an role in arbitrating the bus. The efficiency of bus usage can be determined by the selection of arbitration method. Fixed Priority, Round-Robin, TDMA and Lottery arbitration policies are studied in the conventional arbitration method where the bus priority is primarily considered. In this paper, we propose the arbitration method that calculates the bus utilization of each master. Furthermore, we verify the performance compared with the other arbitration methods through TLM(Transaction Level Model). From the results of performance verification, the arbitration methods of Fixed Priority and Round-Robin can not set the bus utilization and those of TDMA and Lottery happen the error of 50% and 70% respectively compared with bus utilization set by user in more than 100,000 cycles. On the other hand, the bandwidth-award bus arbitration method remains the error of less than 1% since approximately 1000 cycles, compared with bus utilization set by user.

Capacity Optimization of a 802.16e OPDMA/TDD Cellular System using the Joint Allocation Algorithm of Sub-charmel and Transmit Power - Part II : Sub-channel Allocation in the Uplink Using the Channel Sounding and Initial Transmit Power Decision Algorithm According to the User's Throughput (802.16e OFDMA/TDD 셀룰러 시스템의 성능 최적화를 위한 부채널과 전송전력 결합 할당 알고리즘 - Part II : 상향링크에서 Channel Sounding을 통한 부채널 할당 및 사용자의 수율에 따른 초기전송전력 결정 알고리즘)

  • Ko, Sang-Jun;Chang, Kyung-Hi;Kim, Jae-Hyeong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.9A
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    • pp.888-897
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    • 2007
  • In this paper, we propose an uplink dynamic resource allocation algorithm to increase sector throughput and fairness among users in 802.16e OFDMA TDD system. In uplink, we address the difference between uplink and downlink channel state information in 802.16e OFDMA TDD system. The simulation results show that not only an increment of 10% of sector throughput but higher level of fairness is achieved by round-robin using the FLR and the rate / margin adaptive inner closed-loop power control algorithm. The FLR algorithm determines the number of sub-channels to be allocated to the user according to the user's position. Also, we get 31.8% more sector throughput compared with the round-robin using FLR by FASA algorithm using uplink channel state information. User selection, sub-channel allocation, power allocation algorithms and simulation methodology are mentioned in Part I.

Traffic Distributed Processing System Implementation on the Web Sever Networking (웹서버 네트워킹에서의 트래픽분산 처리 시스템 구현)

  • Park, Gil-Cheol;Sung, Kyung;Kim, Seok-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.4
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    • pp.846-853
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    • 2004
  • This paper introduces implementation of a traffic distributed processing system on the Web Sever Networking. The study used two software packages (Packet Capture and Round-Robin Test Package) to check packet quantity from Virtual Network Structure (data generator, virtual server, Serve. 1, 2, 3), and could find out traffic distribution toward Server 1, 2, and 3. The functions of implemented Round-Robin Load Balancing Monitoring System include Round-Robin testing, system monitoring, and graphical indication of data transmission/packet quantity (figures & diagram). As the result of the study shows, Round-Robin Algorithm ensured definite traffic distribution, unless incoming data loads differ much. Although error levels were high in some cases, they were eventually alleviated by repeated tests for a long period of time.

Tongue-Lip Adhesion Using an Alveolar Protector Appliance for Management of Pierre Robin Sequence (피에르 로빈 연속증의 치료로써 치조 보호 장치를 이용한 혀-하순 유착술)

  • Lee, Jang-Won;Park, Beyoung-Yun
    • Archives of Plastic Surgery
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    • v.38 no.4
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    • pp.547-551
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    • 2011
  • Purpose: Pierre Robin sequence is a congenital malformation in which micrognathia causes glossoptosis and airway obstruction. If conservative treatment fails, surgical procedures such as tongue-lip adhesion can be performed. However, this procedure remains a subject of debate, with favorable results being countered by reports of complications. To overcome the above limitations, we revised the traditional method of tongue-lip adhesion using an alveolar protector. Methods: Between 1992 and 2011, a total of eight patients were identified with Pierre Robin sequence and were treated with tongue-lip adhesion. Two of these eight tongue-lip adhesion procedures were performed with an alveolar protector. The operative technique for tongue-lip adhesion was similar to that described in other published reports. The alveolar protector was inserted between the ventral surface of the tip of the tongue and the lower labial sulcus. Results: Tongue-lip adhesion failed in two patients because of wound dehiscence. The primary surgical success rate was 66.7%. In the two tongue-lip adhesion procedures performed with the alveolar protector, we observed no postoperative complications. Conclusion: Resistance to traction of the tongue can be encountered with nonunionized symphysis menti, causing loosening of the traction suture through the symphysis menti. This can lead to backward positioning of tongue, resulting in dehiscence of tongue lip adhesion. The alveolar protector is a good adjunct to tongue-lip adhesion because this method avoids postoperative loosening of the traction suture and wound dehiscence. It is a simple and effective auxiliary method that yields functional improvement.

Algorithm for Deadlock Prevention of Generalized Philosophers' Dining Problem (일반화된 철학자 만찬 문제의 교착상태 예방 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.2
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    • pp.73-78
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    • 2023
  • The dining philosophers problem(DPP) is that five philosophers sit around a round table and eat spaghetti(or noodles) together, where they must have a pair of chopsticks(two) on both sides of them to eat, and if all philosophers have one chopstick on the right, no one can eat because the deadlock occurs. Deadlocks are a problem that frequently occur in parallel systems, and most current operating systems(OS) cannot prevent it. This paper proposes a silver bullet that causes no deadlock in an OS where all processors of 2≤n≤∞ have multiple parallel processing capabilities. The proposed method is a group round-robin method in which ⌊n/2⌋ odd processors form a group and perform simultaneously, and shift right to the next processor when execution ends. The proposed method is to perform two times for even processors, three times for odd processors per one round-robin. If the proposed method is performed n times, even-numbered processors perform n/2 times and odd-numbered processors perform (n-1)/2-times.

A Computationally-Efficient of Fair Queueing without Maintaining the System Virtual Time (시스템 가상시간을 사용하지 않는 효율적인 Fair Queueing)

  • 이준엽;이승형
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.9C
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    • pp.836-841
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    • 2002
  • Packet scheduling is an essential function to guarantee a quality of service by differentiating services in the Internet. Scheduling algorithms that have been suggested so far can be devided into Round-Robin methods and Fair Queueing methods Round-Robin methods have the advantage of high-speed processing through simple implementations, while Fair Queueing methods offer accurate services. Fair queueing algorithms, however, have problems of computational overheads and implementation complexity as their schedulers manage the states of every flow. This paper suggests a new method in which each flow performs the calculation in a distributed way to decide the service order. Our algorithm significantly reduces the scheduler's computational overheads while providing the same level of accuracy with the previous Fair Queueing algorithms.

Pierre Robin sequence with severe scoliosis in an adult: A case report of clinical and radiological features

  • Kim, Jae-Jun;Choi, Dong-Soon;Jang, Insan;Cha, Bong-Kuen;Park, In-Woo
    • Imaging Science in Dentistry
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    • v.49 no.4
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    • pp.323-329
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    • 2019
  • Pierre Robin sequence (PRS) is characterized by the triad of micrognathia, glossoptosis, and airway obstruction. PRS does not have a single pathogenesis, but rather is associated with multiple syndromes. This report presents the case of a 35-year-old woman with PRS and scoliosis. Among the syndromes related to PRS, cerebro-costo-mandibular syndrome (CCMS), which is characterized by posterior rib gap defects and vertebral anomalies, was suspected in this patient. However, no posterior rib gap defect was detected on radiological examinations. Although over 80 cases of CCMS have been reported to date, few cases of PRS with scoliosis alone have been reported. Therefore, this report demonstrated the clinical, radiological, and cephalometric characteristics of an adult patient with PRS and scoliosis, but without rib anomalies.

A Study on the Expanded R/R Scheduling in Priority-based $\mu{C/OS-II}$ Kernel (우선순위 기반의 $\mu{C/OS-II}$ 커널에서 확장된 R/R 스케줄링 연구)

  • 김태호;김창수
    • Journal of Korea Multimedia Society
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    • v.5 no.3
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    • pp.323-330
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    • 2002
  • Recently, the existing embedded real-time operating systems(RTOSs) are being developed in terms of various modified versions in every application fields. Major characteristics and difference of these OSs lie in their distinct development of mechanisms which can be used in various environment and task-scheduling function which can control time-limited contingencies. In this paper, we design and implement round/robin scheduling algorithm based on time-sharing with equal-priority for multiple tasks which are provided preemptive and priority task allocation function in $\mu{C/OS-II}$ version 2.03. We propose the most important event-ready list structure in $\mu{C/OS-II}$; kernel, and provide the running result for multiple tasks with equal priority for the proposed structure.

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Characteristic comparison of various arbitration policies using TLM method (TLM 방법을 이용한 다양한 중재 방식의 특성 비교)

  • Lee, Kook-Pyo;Koh, Si-Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.8
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    • pp.1653-1658
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    • 2009
  • SoC(System on a Chip) has several masters, slaves, arbiter and decoder in bus architecture. Master initiates the data transactions like CPU, DMA and DSP and slave responses the data transactions like SRAM, SDRAM and register. Furthermore, as multiple masters can't use a bus concurrently, arbiter plays an role in bus arbitration. In compliance with the selection of arbitration method, SoC performance can be changed definitely. In this study, we compare the characteristics of various arbitration policies using TLM(Transaction Level Model) method. Fixed priority, round-robin, TDMA and Lottery bus policies are used in general arbitration method. We analyze the merit and demerit of these arbitration policies.