• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.12B
• /
• pp.1677-1685
• /
• 2001

In this paper, we propose a call admission control scheme that can be performed within guaranteeing of required QoS(Quality of Services) in DS-CDMA(Direct Sequence-Code Division Multiple Access) reverse link. It has been performed rely on a physical channel numberonly and based on quality of received signal from MODEM(modulator/demodulator) part in established study. In other methods, the standard for services would have been set from statistical analysis of users\` location and using received power level in BTS(Base Transceiver Station). These ways bring about not only system loads but time delay or great differences from real environment. To solve these problems, we propose a call drop rate estimation algorithm for the purpose of call admission control based on measured value at LNA(Low Noise Amplifier) ports of BTS(Base Transceiver Station) in real time. This method proposed in this paper estimates a quality of offered service in real time, reduce system loads and shorten time delay which is needed to determine the standard for call admission control. But it requires a additional 17W complexity which can measure received signal power in BTS and estimate call drop rate.

• Korean Journal of Microbiology
• /
• v.24 no.2
• /
• pp.79-85
• /
• 1986

We have determined the sequence of $tRNA^{Arg}$ of A. nidulans partially by enzymatic rapid RNA sequencing technique. The sequence was 5'GGCCGGCUGGCCCAAXUGGCAAGGXUCUGAXUACGAAXCAGGAGAUUGCACXXXXXGAGCXXUXXGUCGGUCACCA3' The cloverleaf structure was made from above data. As a result, the anticodon sequence was identified as ACG. This result was confirmed with charging test. The complete sequence was proposed by supplementing the DNA sequence to and by assigning the position of minor bases to this RNA sequence.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2000.10b
• /
• pp.997-1000
• /
• 2000

무선 인터넷 서비스에 대한 요구가 무선기술의 발전과 더불어 증가되고 있다. 하지만 현재의 인터넷 프로토콜인 IPv4에서는 IP의 이동 환경을 지원하지 못한다. 이에 여러 연구가 진행되고 있으며, IETF의 Mobile IP Working Group에서는 기존의 IPv4를 사용하면서도 이동환경을 지원하기 위한 이동 IP에 대한 연구를 진행하고 있다. 이에 본 논문에서는 인터넷에서 계층적이며 효율적인 이동성 지원을 위하여 영역과 도메인, 인터 도메인으로 세분화된 환경에서의 이동성 지원을 위한 기법을 제안한다. 본 논문에서는 하나의 이동 호스트가 특정 멀티캐스트 주소로 인식되어 멀티캐스트 라우팅 프로토콜에 의한 데이터 전송 서비스를 받는다. 이에 지속적인 이동성을 가진 이동 호스트에게 절단점 없는 서비스를 제공하기 위하여 동적 멀티캐스트 경로를 재설정 함으로서 경로 설정에 의한 오버헤드와 데이터전송의 지연을 최소화한다. 이러한 방법은 영역과 도메인, 인터 도메인의 계층적인 이동성을 지원함으로서 핸드오프 지연을 감소시키며. 홈 에이전트와 대응 노드에 부가되는 부하를 줄 일 수 있다.

• Journal of Veterinary Clinics
• /
• v.28 no.3
• /
• pp.310-313
• /
• 2011

A 6-year-old female Shih-tzu dog was referred with left elbow joint mass associated with weight bearing lameness. Ultrasonography demonstrated an encapsulated hyperechoic mass at the left elbow joint. Radiography was performed on elbow joint, chest, and abdomen, but there was no evidence of metastasis. Clinicopathologic examination revealed the existence of neoplastic cells with anisocytosis, pleomorphism and increased nuclear-cytoplasmic ratio. The left forelimb was amputated for cure. Histopathological examination diagnosed the mass as a malignant peripheral nerve sheath tumor. During the 4 weeks follow-up, the patient showed full remission and adopted to walk with remaining three legs. Thereafter, the tumor recurred after 5 months of first surgery at the operation site and other two cutaneuos regions. Cytology test revealed the mesenchymal originated tumor cells with malignancy. These tumors were surgically removed and histopathological examination of the resected tissue revealed the recurrence of primary tumor and metastasis. Metronomic therapy with cyclophophamide (10 mg/$m^2$, PO, sid) and piroxicam (0.3 mg/kg, PO, sid) had been adopted for 5 months. At 26 months of follow up after the first surgery, the dog alive with satisfactory quality of life. Aggressive surgical resection with metronomic chemotherapy should be the most effective treatment for malignant peripheral nerve sheath tumor.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.9
• /
• pp.937-942
• /
• 2008

This paper presents a case history on failures of impeller and shaft due to pressure pulsation at single stage feed water pumps in 700 MW nuclear power plant during commissioning operation. The pumps had been service and had run for approximately $40{\sim}50$ hours. For the most part, the failures of impeller occurred with the presence of a number of fatigue cracks. All cracks were associated with the deleterious surface layer of impeller by visual and metallurgical examination. On-site testing and analytical approach was performed on the systems to diagnose the problem and develop a solution to reduce the effect of exciting sources. A major concern at high-energy centrifugal pump is the pressure pulsation created from trailing edge of the Impeller blade, flow separation and recirculation at centrifugal pumps of partial load. Pressure pulsation due to the interaction generating between impeller and casing coincided with natural frequencies of the impeller and shaft system during 1ow load operation. It was identified that dynamic stress exceeding the fatigue strength of the material at the thin shroud section due to the hydraulic instability at running condition below BEP.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.12A
• /
• pp.1111-1119
• /
• 2005

A single fiber cut can potentially influence a total of 1.6 Tbps of traffic and is surprisingly frequent and results in significant loss of traffic. The survivability as we as the resource utilization of the connection in optical networks is important. Existing protection mechanisms to rapidly recover the failures allocate the backup path just SRLG-disjointed with working path. Those did not consider the unbalanced resource share of backup paths. The backup paths can be centralized on the specific link so that the idle resource is not used. As a result, as those do not efficiently use the resource the whole resource utilization is not so good. So we propose the mechanism to enhance the resources utilization as settling down the unbalanced resource share. Our purpose is to improve the link utilization as distributing the maximum link load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.4
• /
• pp.171-180
• /
• 2004

CDP(handoff Call Dropping Probability) and CBP(new Call Blocking Probability) have been used as two important call level QoS parameters in cellular mobile communications. But, many methods to reduce CDP without considering CBP have been studied, and hand-off call priority scheme has been introduced. But the use of hand-off call priority scheme increases CBP and decreases channel utilization rate depending on the number of reserved channel for priority. In this paper, we propose a CAC(Call Admission Control) algorithm with overflow and preemption to solve the problem caused by considering CDP and CBP in calculation of the number of channel reserved. The problem is the increase of CDP as the traffic load increases. In our CAC algorithm, hand-off call is permitted to use(overflow) unreserved and unused channel if there is no reserved and unused channel, and new call is permitted to use(preemption) the channel overflowed by hand-off call if there is no unreserved and unused channel. This mechanism of calculation of the number of reserved channel and CAC algorithm is expected to increase channel utilization rate, and can be applied to media-based QoS provision in cellular mobile communications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.2
• /
• pp.195-204
• /
• 2020

To help solve the problems of how to set the optimal sawing force and the optimal controller parameters for different sawing conditions, a mathematical model of a proposed sawing system was established according to the principle of sawing force control. The conventional PID control method was then used for further research of the closed-loop control of the sawing force. Finally, through simulation and experimental research, the influence rule of the controller parameters and sawing load on the control performance and the relationships between the sawing width and controller parameters (proportion coefficient) and the sawing force setting value were obtained, from which a system scheme for intelligent sawing control of a band sawing machine was proposed. The research shows that the sawing efficiency of the intelligent sawing system was 18.1 (48%) higher than that of the original sawing system when sawing a grooved section sawing material, which verifies the good control effect of the proposed scheme.

• Restorative Dentistry and Endodontics
• /
• v.35 no.4
• /
• pp.257-266
• /
• 2010

The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizes.

• Korean Journal of Social Welfare
• /
• v.57 no.3
• /
• pp.305-335
• /
• 2005

This paper is a result from validation study for SPDA(A Screening Scale For Potential Drug-use Adolescents) created in 2003 and newly developed during 2004. SPDA aims to screen adolescents in their early stage of drug-use and to help practitioners make a preventive approach for the adolescents. 4307 junior and senior high school students were selected as primary research subjects by stratified and quota sampling methods. 305 adolescents on probation were also selected as a comparison group and asked to answer the same questionnaire. Reliability for SPDA recorded 0.914, which proved to be better than previous year's (0.898). Exploratory and confirmatory factor analyses to test construct validity proved that SPDA could be divided into 7 factors and that each factor structure of SPDA could be a proper measurement model with high level of fitness and factor loadings. Discriminant analysis to test predictive validity confirmed that SPDA could classify the adolescents excellently by the frequency of drug-use, with hit ratio of 86.6 percent(78.8% and 87.4% for junior and senior high school students respectively). For concurrent validity test, Hare Home Self-Esteem Scale, Hare School Self-Esteem, Zuckerman-Kuhlman Sensation-seeking Scale were employed to find correlation with SPDA and all the three scales had significant Pearson correlation coefficients with SPDA. Known-groups validity test indicated that SPDA had an adequate power to classify out adolescents on probation from those in schooling, with a hit ratio of 71.8 percent. Cut-off point to detect adolescents with high risk of substance use was 77, which indicated approximately T score, 55 (0.5 SD), satisfying sensitivity, specificity, and efficiency criteria.