• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.87-94
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• 2008

Message races should be detected for debugging effectively message-passing programs because they can cause non-deterministic executions of a program. Previous tools for detecting message races report that message races occur in every receive operation which is expected to receive any messages. However message races might not occur in the receive operation if each of messages is transmitted through a different logical communication channel so that their incorrect detection makes it a difficult task for programmers to debug programs. In this paper we suggest a tool, MPIRace-Check, which can exactly detect message races by checking the concurrency between send/receive operations, and by inspecting the logical communication channels of the messages. To detect message races, this tool uses the vector timestamp to check if send and receive operations are concurrent during an execution of a program and it also uses the message envelop to inspect if the logical communication channels of transmitted messages are the same. In our experiment, we show that our tool can exactly detect message races with efficiency using MPI_RTED and a benchmark program. By detecting message races exactly, therefore, our tool enables programmers to develop reliable parallel programs reducing the burden of debugging.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1619-1629
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• 2016

We study an efficient transmission protocol for the cellular-aided device-to-device communication model. In particular, two source-destination pairs communicate with the help of unlink and downlink cellular links. For the proposed scheme, two transmitters send their messages and the base station and two receivers receive at the first phase. Then, at the second phase, the base station sends the XOR of the messages to two receivers and they try to decode their own messages from the received signals after the first and second phases. We analyze the outage-based throughput achievable by the proposed scheme and demonstrate by simulations that the proposed scheme provides an improved outage performance compared to the conventional device-to-device communication schemes.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.684-690
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• 2006

This paper proposes a message transmission model for hard real-time communications of periodic messages on a switched Ethernet and also proposes an algorithm to schedule the messages to be transmitted within their deadlines. The proposed scheduling algorithm is a distributed one and is peformed by the source and the destination nodes without the modification of the operational features of the standard Ethernet switch. When a new periodic message needs to be transmitted, it is first checked whether it can be scheduled on both the transmission and the reception links without affecting the already-scheduled messages, and a feasible schedule is made for the new message if it is schedulable. The proposed scheduling algorithm guarantees the transmission of periodic messages within their deadline and allows flexible message transmission on a hard real-time switched Ethernet through the dynamic addition of new periodic messages during run-time.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.3
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• pp.125-134
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• 2014

This paper proposes a multi-agent message transport architecture to support application areas which need fast message communications for close collaboration among agents. In the FIPA(Foundation of Intelligent Physical Agents) agent platform, all message transfer services among agents are in charge of a conceptual entity named ACC(Agent Communication Channel). In our multi-agent message transport architecture, the ACC is represented as a set of system agents named MTSA(Message Transfer Service Agent). The MTSA enables close collaboration among agents by supporting asynchronous communication, by using Reactor pattern to handle agent input messages efficiently, and by selecting optimal message transfer protocols according to the relative positional relationships of sender agents and receiver agents. The multi-agent framework SMAF(Small Multi-Agent Framework), which is implemented on the proposed multi-agent message transport architecture, shows better performance on message transfer among agents than JADE(Java Agent Development Environment) which is a well-known FIPA-compliant multi-agent framework. The faster the speed of message transfer of a multi-agent architecture becomes, the wider application areas the architecture can support.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1331-1334
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• 2001

컴퓨터가 보편화됨으로써 여러 가지 방법의 메시지교환을 위한 환경이 제공되고 있다. 일반적으로 웹 서버를 통한 메시지교환이 이루어지고 있으며, 이러한 방법은 보안에 취약한 형태를 지니고 있음이 분명하다. 경우에 따라서는 보안을 염두에 두고 통신을 한 필요가 있으므로 똔 논문에서는 통신하는 두 컴퓨터이외의 다른 연결서버를 이용하지 않고, 메시지를 교환하고자 하는 컴퓨터 상호간에 어느 한 대는 서버, 다른 한 대는 클라이언트의 역할을 맡아 직접 메시지를 교환하는 시스템을 설계 및 구현하고자 한다.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.143-154
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• 2003

There is a growing trend in developing system for distributed mobile system that supports services - job flow management, video conference, replicated data management and resource allocation. Supporting these services, applications have to use causally ordered message delivery. Previous proposals that provide causally ordered message delivery have problems such as communication overhead, message delaying, scalability, computing overload of mobile host. In this paper, we proposed efficient protocol for causally ordered message delivery using the methods that MSS maintains dependency information matrix between MSS and MH, Piggybacking dependency information about each immediate predecessor message. Proposed algorithm, when compared with previous proposals, provides a low message overhead, and low probability of unnecessary inhibition in delivering messages. Also, it consider resource restriction of MH and low bandwidth of wireless communication by computing most of algorithm at MSS, and reduce processing delay by executing causally ordered message delivery a unit of MH.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.343-345
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• 2006

본 연구는 센서 네트워크용 운영체제인 TinyOS의 메시지 길이를 효율적으로 관리하여 저전 손실을 줄인 센서 네트워크의 연구이다. 센서 네트워크에서 가장 큰 전력 손실을 가져오는 부분은 RF통신 부분이라 할 수 있다. 메시지의 길이에 따라 길이가 길면 더욱더 통신 시간이 길어지므로 전력 손실은 커질 것이다. 이와 같은 토픽에 따라 메시지의 길이를 줄여 줌으로써 RF통신에 이용되는 전력을 줄여 보고자 하는 것이다. 사용된 시뮬레이터는 TinyOS에서 자체 제공 되는 TOSSIM을 이용 하였으며 MCU가 데이터를 처리하는데 소모되는 전력과 RF 통신에 따라 소모되는 전력을 나타내었다. 시뮬레이션을 통해 메시지의 길이가 줄어들면 전력 소모가 줄어드는 것을 확인 할 수 있었다. 더 나아가 거리간의 차이에 의한 전력 소모량도 연구 되어야 할 것이다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.3
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• pp.568-577
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• 2017

IEEE Std 1609.2 was defined for the support of communication security functions in the WAVE (Wireless Access in Vehicular Environments) system. IEEE Std 1609.2 defined the message structures of the security services and managements on the vehicular communication by using ASN.1 (Abstract Syntax Notation One). Also, this security message structures shall be encoded using the COER (Canonical Octet Encoding Rules). In this paper, we designed and implemented the IEEE Std 1609.2 message encoder/decoder handling the security messages defined in IEEE Std 1609.2. The designed encoder/decoder consists of three modules as follows : a module generating the message of C language data structures in accord with IEEE Std 1609.2 message structures, a message encoder module, a message decoder module. And the encoder/decoder was implemented on the Linux environment. Also we analyzed the performance by measuring the performance speed of the encoder/decoder implemented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1113-1121
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• 2010

The Vehicle Safety Communications (VSC) is one of VANET applications for preventing vehicle accidents, and it utilizes vehicle-to-vehicle communication to exchange emergency messages. To propagate such messages in VSC, several schemes based on selective flooding have been proposed. Their common idea is that an emergency message is relayed by one of vehicles receiving the message. However, the schemes do not consider the transmission errors and duplications of an emergency event. In the schemes, if there are transmission errors and a vehicle detects a hazard, there may be vehicles which fail to receive an emergency message. If k vehicles detect a hazard, k emergency messages are created and propagated. The duplications of an event increase reliability of the message delivery but decrease efficiency. In this paper, we propose an emergency message delivery scheme which is efficient and robust to transmission errors. Our proposed scheme utilizes clustering for massage aggregation and retransmissions in a cluster. It also uses an acknowledgment mechanism for reliable inter-cluster communication. Our simulation results show that the proposed scheme outperforms Least Common Neighbor Flooding which is one of the selective flooding schemes.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.4 no.1
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• pp.16-25
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• 1986

Data communication is the transmission of coded information between terminals and computers or between multiple computers. A large, complex, and geographically dispersed present industrial society requires processing of real-time inputs that must be collected from many different locations and production of real-time outpts that must be distributed to many defferent locations. As one of many alternatives to meet the above requirement, a data communication system can be used.