서비스 품질 조정을 고려한 동기화 전송 방안

배시규 東洋大學校 産業技術硏究所 1999 東洋大學校 産業技術硏究所 論文集 Vol.1 No.1

When continuous media are transmitted over the communication networks, asynchrony may occur due to a random transit delay, which can not maintain temporal relationships among packets. There exist two types of the transport protocol which considers for guaranteed or non-guaranteed resource networks. So do synchronization schemes. The former applies a resource reservation technique and maintains delay characteristics, however, the latter supplies a best-effort service. In this paper, I propose a intra-media synchronization scheme to transmit continuous media on general networks not guaranteeing a bounded delay time. The scheme controls transmission times of the packets by estimating next delay time with the delay distribution. So, the arriving packets may be maintained within a limited delay boundary, and playout will be performed after buffering to smoothen small delay variations. The continually increasing delay to network overload causes buffer underflow at the receiver. To solve it, the transmitter is required to speed up instantaneously. Too much increase of transmission-rate may cause network congestion. At that time, the transmitter performs media scaling-down by dropping the current packet when informed excessive delay from the receiver.

추측과 반박을 통한 수학적 발견논리

류시규,김희정 동국대학교 교육연구원 2000 교육문제연구 Vol.15 No.-

For a long time the mathematical knowledge was understood as the group of the eternal truth, proved through the deductive inference of the absolute truth. Therefore, we regarded as all the mathematical prepositions as the absolute truth and any refutation or any presentation of objection was not necessary. Such point of view affected the mathematics education and caused the students to regard the mathematical knowledge as an informative one acquired from the accurate verification rather than from critical approach. Thus the mathematical knowledge were provided mechanically to the students in rather memory-oriented way, which, as a result, becomes one of the main reasons that the students regard the mathematics as an uninteresting and dull learning. In 20th century, however, lots of endeavors were made to improve such mathematics education. As one of the studies, more attention started to be paid to not only the informative aspect of mathematics but the methodological aspect and the importance of speculation. Affected by G. Polya, an mathematician who studied this matter and K. Popper who ever led the critical falsificationalism, Lakatos insisted that the mathematic education should provide the students with more opportunity to consequently get into more reasonable knowledge, rather than just a simplified calculation-oriented class or mechanical thinking, like the mathematics has been developed steadily all through long historical steps. Lakatos also argued that such improvement in inference capability can be accomplished through comparing the opinions by discussions with others and reaching more mutually reasonable point. And it will correspond to the pursuit of rationality, ultimate goal of mathematics education. In this paper, therefore, we would like to examine into the features of mathematical knowledge and its progressive process which Lakatos ever stated and then I would try to apply it to the models of mathematics class.

패킷망에서 전송율 제어와 패킷 폐기에 의한 연속 미디어 전송 방안

배시규 한국정보전략학회 1999 추계공동학술대회 논문집 Vol.- No.01

통신망을 통하여 시간 연속(continuous) 미디어를 전송하면 통신망의 부하 변동에 따라 운송지연(transit delay)이 일정하지 않으므로 수신측에 도착하는 패킷간에 원래의 시간 관계가 유지되지 않는 비동기 현상이 나타난다. 현재 제안된 여러 동기화 방안들은 운송 지연 특성을 보장하는 자원 보장형 통신망과 운송 지연 특성이 보장되지 않아 변화의 폭이 큰 자원 비보장형 통신망 환경을 고려한 2가지 형태가 존재한다. 자원 보장형 통신망은 최소 및 최대 운송 지연 시간을 예약이나 협상을 통해 전송 기간동안 계속 유지하는 반면, 자원 비보장형 통신망에서는 가능한 최대의 대역폭을 사용하는 최대 노력 (best-effort) 서비스를 사용한다. 이 논문은 패킷망이나 인터넷과 같은 자원 비보장형 통신망 환경에서 통신망의 부하 변화에 동적으로 적응하여 동기화된 전달(playout)을 제공하는 미디어내 동기화 방안(Inter-media Synchronization)에 관한 것이다. 본 논문에서 제안하는 방안은 데이터 전송 경로의 운송지연 통계치를 사용하여 다음 전송할 패킷의 운송 지연을 추정하여 송신 시간을 조절함으로써, 통신망의 부하로 인한 운송 지연의 변화가 크더라도 수신 패킷의 도착 시간을 일정한 범위 내로 유지한다. 또한, 통신망의 부하가 지속적으로 증가하여 연속되는 패킷의 운송 지연이 점차 늘어나면 전송률을 높이는 것만으로 문제를 해결할 수 없을 뿐만 아니라 오히려 혼잡을 발생시킬 가능성이 있다. 따라서, 통신망의 대역폭에 맞추어 일부 전송 패킷을 폐기함으로써 실제적인 전송률을 조정하였다. 이 방안은 수신측의 버퍼가 충분하지 않거나, 버퍼 지연 시간이 제한적인 대화형 응용에서 연속 미디어를 전송하는데 적합하다. When continuous media are transmitted over the communication networks, asynchrony which can not maintain temporal relationships among packets may occur due to a random transit delay. There exist two types of synchronization schemes; for guaranteed or non-guaranteed resource networks. The former which applies a resource reservation technique maintains delay characteristics, however, the latter supply a best-effort service. In this paper, I propose a intra-media synchronization scheme to transmit continuous media on general networks not guaranteeing a bounded delay time. The scheme controls transmission times of the packets by estimating next delay time with the delay distribution. So, the arriving packets may be maintained within a limited delay boundary, and playout will be performed after buffering to smoothen small delay variations. The continually increasing delay due to network overload causes buffer underflow at the receiver. To solve it, the transmitter is required to speed up instantaneously. Too much increase of transmission-rate may cause network congestion. At that time, the transmitter drops the current packet when informed excessive delay from the receiver.

남ㆍ북한 수학 교육과정 비교ㆍ분석 : 국민공통기본과정 9-가, 9-나를 중심으로

유시규,안순주 동국대학교 교육연구원 2005 교육문제연구 Vol.16 No.-

2002년도 발행된 고등중학교 1, 2, 3학년의 북한의 수학교과서와 2004년도 발행된 제7차 수학교육과정의 교과서를 중심으로 학교수학의 내용의 현상학적 특징을 비교ㆍ분석 하고자 한다. 본 논문에서 언급하는 바와 같이, 북한의 수학교과서에서는 상당히 많은 용어들이 이해하기가 난해한 한글용어로 자리메김하고 있다. 원래 중등학교 수학용어들의 대부분은 광복 이전에 사용하던 한자용어를 남북한에서 각각 독자적인 변화과정을 거쳐서 오늘에 이르게 되었다. 물론, 그의 핵심적인 변화는 한자 용어를 한글화하는 것이었다. 또한, 기존의 여러 논문들은 북한의 수학교육의 내용만 다루어고 있는데 비하여, 본 연구에서는 우리의 제 7차 교육과정 수학과 해설서에 준해서 북한의 통합 후의 교과서를 분석하여, 북한 수학 교과의 성격, 목표, 내용, 교수 학습 방법, 평가에 대한 부분을 조사 및 분석하였다. A half century has passed since Korean peninsula was divided into South and North Korea. So there are many differences in the society, politics, economy, culture and education between South and North Korea. Recently, there has been increased concerning reunification of South and North Korea. As a response to this growing mood of unification, the people who are related with mathematics education start to study North Korea's education ideology, goals and system. This paper attempts to analyze secondary mathematics curriculum in North Korea published by 2002 compared with South Korea's curriculum. As the results of this analysis and comparison, We can find some similarities and differences. Although there are some similarities in the form and content, many differences are also found ; view points of teaching, approach methods, and terms. On the basis of the above findings, We attempted to make some suggestion for the researches preparing for the unification in the area of secondary mathematics education. We would like to become a guide in the preparation for the unified mathematics curriculum ; for the unified Korea in the future.

스트리밍 제어 방안의 성능 평가

배시규 동양대학교 산업기술연구소 2001 東洋大學校 産業技術硏究所 論文集 Vol.3 No.1

Continuous media, unlike discrete media, have the limitation for a transmission-rate and delay variation. When continuous media are transmitted over a network, transit delays increase or some packets may be lost unless bandwidth is enough. Congestion and synchronization control, which are close relationships, are needed to solve the problem. This paper is about the performance evaluation of the congestion and synchronization control scheme which was proposed by us. The scheme was designed to avoid congestion and support synchronization by send-rate control, media scaling, and buffer control on a non-guaranteed network like Internet.

대학의 교양 컴퓨터교육 과정 연구 : 동양대를 중심으로

배시규 동양대학교 2008 동양대학교 논문집 Vol.13 No.1

The 7th National Curriculum for elementary through high school contains computer-related subjects. General computer education should be done in consideration of the National Curriculum's objectives. I surveyed the present status of the computer subjects from elementary to high school curricula. After analyzing I propose a proper direction for general computer education in university, especially for Dongyang University.

REAL™시뮬레이터를 사용한 동기화 프로토콜의 성능 시험

배시규 동양대학교 2000 동양대학교 논문집 Vol.6 No.1

In this paper, the Multimedia Synchronization Protocol has been tested using the REAL network simulator, which has been developed at Cornell university, USA. The REAL network simulator was developed to study the dynamic behavior of flow and congestion control schemes in packet switch data networks. However, it is not appropriate to testing the media synchronization schemes directly. I modified the REAL simulator' main code and added new functions appropriate to the synchronization operation. The test results are very useful for the performance evaluation of the synchronization schemes.

JMF(Java Madia Framework)^TM를 사용한 비디오 방송 시스템

배시규 동양대학교 2002 동양대학교 논문집 Vol.8 No.1

JMF API(Application Programming Interface) enables time-based media to be added to Java applications/applets, which can capture, playback, stream and transcode mutiple media formats. The latest JMF 2.1.1 includes de facto RTP(Real Time Protocol) usage for transmitting time continuous media to multiple participants. In this paper, I implemented a video broadcasting system over a network using JMF, and tested it in Intranet. Some video data are transmitted from the server to the multiple clients and played back at the each client.

서비스 거부 공격에 대비한 echo 서버

배시규 東洋大學校 産業技術硏究所 2002 東洋大學校 産業技術硏究所 論文集 Vol.4 No.1

A Denial-of-service attack are one of the serous problems usually encountered in Internet. It is occurs when an Internet server is flooded with a nearly continuous stream of bad requests, which deny legitimate users an opportunity to access to an server or may crash the server. This paper is about an enhanced 'Echo' service to protect an host from Denial-of-service attacks. A server program has been modified to adapt to too frequent requests. So, the enhanced server program will limit services to bad requests.

멀티캐스트 IP를 사용한 영상발표시스템의 구현

배시규,권만희 동양대학교 산업기술연구소 2000 東洋大學校 産業技術硏究所 論文集 Vol.2 No.1

In this paper, we implemented the Video Presentation System using Multicast IP in MBone(Multicast Backbone) environment. The software, which is composed of the transmitter and the receiver, has been developed with Visual C++, Video For Windows Development Toolkit, and Winsock. The implemented system was tested in LAN environment equipped with the multicast router, and is being tested over the Internet.