광역 네트웍에서의 음성패킷의 적응재생 지연조정 방안

신병철 충북대학교 컴퓨터정보통신 연구소 2000 컴퓨터정보통신연구 Vol.8 No.2

본 논문에서는 적응적으로 음성패킷 재생지연을 결정하는 방안을 제안한다. 재생 지연은 패킷이 네트웍 내의 여러 노드를 거치면서 겪는 네트웍 지연과 수신단에서 수신후 재생하기까지의 버퍼링 지연의 합으로 이루어진다. 음성 패킷의 네트웍 지연 평균을 추정하여 용인할 수 있을 만큼의 재생 손실을 유지하면서 최대한 짧은 버퍼 지연을 갖도록 재생지연 값을 산출한다. 이러한 재생 지연은 기본적으로 동기 단위인 음성의 talkspurt마다 새로이 결정된다. 또한, 네트웍 지연의 변화가 talkspurt 중간이나 silence 구간에 크게 일어나는 경우에도 손실률을 낮추기 위해 재생 지연을 새로이 결정한다. Talkspurt내에서 패킷들은 발생 주기와 동일한 주기로 재생된다. 재생지연 값보다 큰 네트웍 지연을 가지고 도착하는 피킷들은 재생되지 못하고 손실로 처리된다. 제안된 음성 재생지연 결정 방안은 변화하는 네트웍 지연에 따라 적절한 재생 지연을 결정하여 지연 시간을 줄이면서도 낮은 재생 손시률을 얻을 수 있다. In this paper, a mechanism is proposed to adjust adaptively the playout delay of voice packets. The playout delay consists of the network delay which packets incur while traversing the network and the buffering delay while packets wait till playout at the receiver. The playout delay is till calculated from the estimate for mean network delays so that no more than the acceptable fraction are lost and that the buffering delay is reduced as small as possible. Basically, the playout delay changes from talkspurt to talkspurt. In addition, when the network delay changes radically in the middle of talkspurt or silence, the playout delay is recalculated to reduce the loss. Within a talkspurt, packets are played out in a periodic. manner, thus reproducing their periodic generation at the source. If a packet having a larger network delay than its playout delay is received at the receiver, the packet could not be played out and should be dropped. The proposed algorithm in this work, which chooses the playout delay in the face of varying network delay, can achieve short delay and a low rate of lost packets.

ROHC 압축 기법을 이용한 SCTP 헤더 압축

신병철,송희옥 충북대학교 컴퓨터정보통신 연구소 2006 컴퓨터정보통신연구 Vol.14 No.2

본 논문에서는 무선을 포함한 패킷 전송에서의 효율성을 위해 차세대 전송 계층 프로토콜인 SCTP에 ROHC(RObust Header Compression)를 적용한 ROHC 프로파일 7(ROHC-SCTP)방식을 제안한다. 제안된 ROHC-SCTP는 SNR(Sequence Number ROHC)-SCTP의 1 또는 2 바이트 길이의 새로운 필드를 SCTP 패킷 헤더에 추가하여, SCTP 멀티 스트림을 acknowledgement 스트림과 data 스트림으로 나누어 헤더 압축을 하며, 동기화 손실이 발생한 경우 context를 복구하는데 사용될 수 있도록 설계되었다. ROHC-SCTP의 제안을 통해 SCTP 헤더의 오버헤드 율을 최대 25% 까지 감소할 수 있으며 대역폭 또한 최대 5% 정도 절약할 수 있다. In this paper, we propose a new profile, ROHC(RObust Header Compression) profile 7, for SCTP with ROHC for applying robust header compression SCTP, which is a transport layer protocol. The proposed new profile 7 adds a new field of 1 or 2 byte size on the existing SCTP packet header, which can make the SCTP stream to be divided into acknowledgement stream and data stream. In addition, the classification of the stream can be used for recovering fault context. Consequently, in case that the proposed ROHC-SCTP is used, it is possible to reduce the SCTP header overhead rate and the bandwidth can also be saved.

형상기억합금 기반 공구 클램핑장치의 자동 공구교환 시스템 개발

신우철,노승국,김병섭,박종권 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

This study developed an auto tool change system of the SMA-based tool clamping device for applications of micro-machine tools. This paper first introduces clamping/unclamping mechanisms of the auto tool change system and its basic configuration. In addition, it shows experimental results of times needed for clamping/unclamping operations of a prototype of the auto tool change system. The average values were estimated to 7.2(s) and 2.6(s) respectively. These results confirm that the auto tool change system is feasible.

B-ISDN에서 비연결형 서비스 지원을 위한 CLS간 대역폭 재할당 알고리즘

신병철,류원모 충북대학교 컴퓨터 정보통신 연구소 2000 컴퓨터정보통신연구 Vol.8 No.1

본 논문에서는 Broadband Integrated Services Digital Network(B-ISDN)에서 비연결형 서비스를 지원하기 위한 비연결형 서버(Connectionless Server. CLS)간의 대역폭 재할당 알고리즘을 제안하였다. 이 방안에서는 버퍼의 임계치와 타이머를 사용하여 수신 노드와 송신 노드사이의 대역폭 재협상 과정이 일어나게 된다. 송신 노드의 버퍼가 임계치를 초과하면 대역폭 재협상이 시작되고, 대역폭은 수신 노드가 가지고 있는 타이머에 의해 주기적으로 일정분만큼 증가하게 된다. 그러나 충분한 대역폭이 할당되어 버퍼가 비게 되면 송신 노드는 대역폭을 줄이게 되고 이와 관련한 신호를 수신 노드로 보내게 된다. 시뮬레이션 결과에 의하면 제안한 알고리즘은 기존의 대역폭 재협상 알고리즘인 Variable Bandwidth Connection(VBC) 방식에 비해 패킷 손실률과 평균 지연 등의 성능이 더 우수하게 동작할 수 있음을 보여준다. In this paper, we propose a time-dependent dynamic bandwidth management algorithm that allocates the bandwidth between two Connectionless Servers(CLSs). If the queue in the source node exceeds the threshold, the source node starts to renegotiate the bandwidth by sending a bandwidth increment request message. The destination node allows incrementing a fixed amount until the source node sends a bandwidth release message and uses a timer to generate next allowable message. However, if the queue is empty for a fixed duration, the source node decrease the bandwidth by sending a bandwidth release message. Simulation results show the proposed algorithm offers a lower burst loss rate and average delay than those of the existing bandwidth reallocation algorithm. Variable Bandwidth Connection(VBC).

경도비만아동의 등부하(5kg)와 중도비만아동의 무부하 최대운동시 호흡순환기능 비교

안병철,김종인,이재규,김태운,신군수,문혜경 釜山大學校 附設 體育科學硏究所 1998 體育科學硏究所 論文集 Vol.14 No.-

The purpose of this study was to examined the comparison of cardio-respiratory functions at maximum exercise in back load of light-obesity and without load of middle-obese elementary schoolboys. The subjects were 16 obese elementary schoolboys(eight boys : light obesity(5kg load), eight boys : middle obesity (without load)) The conclusion of this study was as follow ; 1. There were no significant in VEmax, Vco2max, Vo2max and BF. 2. Without load of middle obesity were significant increase in Vo2max/wt and HRmax.

Haloperidol Decanoate치료중인 정신분열증 환자의 혈청 할로페리돌 농도에 관한 연구

양병환,고용철,김광일,강보경,이경옥,신호상 漢陽大學校 精神健康硏究 1997 精神健康硏究 Vol.16 No.-

증발과 응결에 대한 국민 학생들의 개념 조사

최병순,김효남,강순희,신인철 한국교원대학교 과학교육연구소 1993 청람과학교육연구논총 Vol.3 No.1

The purpose of this study was to investigate and analyze the conception of elementary school students on evaporation and condensation, and then to verify the types of the conception. Forty-eight children from six elementary schools were sampled by stratified random sampling in Seoul and other provinces. They responded to the questionaire and the interview. This study was carried out according to the process of the basic study, the preliminary study, and the main study. The materials collected were classified and analyzed according to the types of children's ideas. The findings of this study were as follows: 1. The vocabulary used to describe the evaporation phenomena varied according to the situations, and the scientific term "evaporation" was more frequently used by the older groups. 2. Most children answered that the last location of water were air/sky/cloud. Air/cloud which represents the scientific conception of the location of water were mentioned by children of all ages. The higher the grade of the children were, the more scientific conception the children mentioned, however. 3. Most children referred to the heat as the factor of evaporation. Wind, on the other hand was mentioned by less than 10% of lower graders, and by about 30% of higher graders. 4. The result of asking children whether they thought it was possible to get the evaporated water back showed that about 70% of lower graders denied the possibility of the water being reversible. About 60% of higher graders, however, recognized that the water will be returned as rain or condensation. This increase may be associated with formal teaching of water cycle. 5. In the ideas of evaporation and condensation, some of the children have supernatural ideas and animism, which are most younger chilren's characteristics.

運動負荷前後 肥滿女中生의 血中 Glucose, Insulin 및 Apolipoprotein 代謝變化

김태운,신군수,김종인,이광무,김성헌,안병철,고기준 釜山大學校 附設 體育科學硏究所 1994 體育科學硏究所 論文集 Vol.10 No.-

The purpose of this study was to determin a study on the change of blood glucose, insulin and apolipoprotein metabolism before and after maximal exercise in obese middle School girls. The subjects were included 2 groups (each group n=6) : obese group, non-obese group. The measurement variables were blood glucose, insulin and apolipoprotein before and after maximal exercise. The conclusion of this study was as follows: 1. Changes in glucose 1) Obese group had no significant differences by maximal exercise. 2) Non-obese group has been increased significantly by maximal exercise (P<.05). 3) No significant difference was found between two groups. 2. Changes in insulin 1) Obese group had non-obese group had no significant differences by maximal exercise. 2) Obese group has been increased significantly when comparing with non-obese group (P<.05). 3. Changes in apoliporprotein 1) Two groups in Apo-AI has been increased significantly pre and post maximal exercise(P<.05). 2) No significant difference on Apo-AI was found between two groups. 3) Obese group and non-obese group in Apo-B had no significant differences by maximal exercise. 4) No significant difference on Apo-B was found between two groups.

규칙적인 유산소성 운동이 비만아동들의 신체구성 및 호흡순환기능에 미치는 영향

김태운,신군수,김종인,이광무,김성헌,안병철,고기준,한재웅,이재규 釜山大學校 附設 體育科學硏究所 1997 體育科學硏究所 論文集 Vol.13 No.-

The purpose of this study was to examined the effect of supervised regulary aerobic exercise program with cardiorespiratory function of obese children. The subjects were 16 obese Childrens(elementary school 4∼5 grade), and engaged in regulary aerobic exercise program for 9 weeks(5 days/week, 100 min/day, 60∼70% HRmax) with mountain climbing, basketball and football. The items of cardiorespiratory function measured VEmax, HRmax, RQmax, VCO₂max, VCO₂max, VCO₂max/kg and BFmax after treadmill exercise load. The conclusion of this study was as follows ; 1. In body composition, there were significant decrease(P<0.001) after aerobic exercise for 9 weeks in body weight, percent body mass index 2. In cardiorespiratory function, there were significant increase(P<0.001) after aerobic exercise for 9 weeks in VEmax and VCO₂max by treadmill exercise load. 3. In cardiorespiratory function, there were significant increase(P<0.001) after aerobic exercise for 9 weeks in VO₂mex and RQmax by treadmill exercise load. 4. In cardiorespiratory function, there were significant increase(P<0.001, P< 0.01) after aerobic exercise for 9 weeks in VO₂max/kg and BFmax by treadmill exercise load.

여중생들의 신체조성과 심폐기능 및 심박수 회복율에 관한 비교 연구 : 비만 여중생과 정상 여중생을 중심으로

김태운,신군수,김종인,이광무,김성헌,안병철,고기준,한재웅,이재규 釜山大學校 附設 體育科學硏究所 1996 體育科學硏究所 論文集 Vol.12 No.-

The purpose of this study was to compare and analyze the relation between body composition, cardiorespiratory functions and percent heart rate recovery in obese and normal middle school female students. We used total of 12 middle school female students(3rd grade) as subject and devided them into two groups : The measurement items of cardiorespiratory functions were HR, VE, RQ, VO₂, VCO₂, VO₂/kg, O₂pulse, VE/VO₂, VE/VCO₂, before and after treadmill exercise load. The statistical analysis were M±SD and t-test for groups(α=.05) using ?? statistical package. The conclusion of this study was as follows ; 1. In 5 items(FM, LBM, %Fat, TBW, BMI) all of body composition, obese group has been significantly higher than normal group(P<0.01). 2. In heart rate and VO₂ of resting(before exercise loads) cardiorespiratory functions, normal group has been significantly higher than obese group(P<0.05). 3. In VEmax of cardiorespiratory functions after exercise loads, obese group has been significantly higher than normal group(P<0.05), and in VO₂max, obese group has been significantly higher than normal group(P<0.01). 4. In 1, 3, 5 minute percent recovery all of percent heart rate recovery after exercise loads, normal group has been higher than obese group but there was no statistical significant difference.