• 대한조선학회논문집
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• 제60권1호
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• pp.48-56
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• 2023

This paper implements many-to-many communication between users and develops a multi-functional smart helmet for worker protection and environmental safety in the shipbuilding and shipping industry. First, the communication situation is recorded in the field to perform signal processing for noise that interferes with communication. Then, it deals with the contents of developing smart helmets, data acquisition, algorithms, and simulations. The simulation results analyzed by applying the adaptive algorithm are shown, and their usefulness is confirmed. In conclusion, looking at the optimization process for the convergence factor of the Least Mean Square and Filtered-x Least Mean Square Adaptation Algorithm was possible. It is thought that it has laid the foundation for implementing many-to-many communication, the function of smart helmets that reduces or removes various noises at the shipyard in the future.

• 전기학회논문지
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• 제66권1호
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• pp.179-185
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• 2017

Communication technologies hold a significant place in the swarm flight of drones for surveillance, inspection of disasters and calamities, entertainment performances, and drone collaborations. A GCS(ground control station) for the control of drone swarms needs its devoted communication method to control a large number of drones at the same time. General drone controllers control drones by connecting transmitters and drones in 1:1. When such an old communication method is employed to control many drones simultaneously, problems can emerge with the control of many transmitter modules connected to a GCS and frequency interference among them. This study implemented a transmitter controller to control many drones simultaneously with a communication chip of 2.4GHz ISM band and a Cortex M4-based board. It also designed a GCS to control many transmitter controllers via a network. The hierarchical method made it possible to control many more drones. In addition, the problem with frequency interference was resolved by implementing a time- and frequency-sharing method, controlling many drones simultaneously, and adding the frequency hopping feature. If PPM and S.BUS protocol features are added to it, it will be compatible with more diverse transmitters and drones.

• ETRI Journal
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• 제29권6호
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• pp.745-754
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• 2007

In this paper, we present the Enhanced Communication Transport Protocol-Part 5 (ECTP-5), which provides scalable and reliable multicast communication service for many-to-many applications by constructing high quality recovery trees from two-layer logical trees and repairing the losses via unicast automatic repeat request-based error control. In order to realize the protocol, we developed feasible protocol architectures and building blocks including additional functions which deal with engineering details, such as membership dynamics and sender coordination. Experimental results show that ECTP-5 scales well with various session sizes and packet loss rates in terms of control overhead and recovery latency.

• 인터넷정보학회논문지
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• 제16권3호
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• pp.13-20
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• 2015

본 논문에서는 회의, 포럼, 세미나 등의 다수인이 모여 있는 집단에서 명함을 교환할 때, 일대일로 수차례 교환해야하는 불편함을 개선하기 위해 다대다 통신방식으로 효과적으로 명함을 교환할 수 있는 시스템을 제안한다. 제안한 시스템은 Near Field Communication(NFC) 통신기반으로 서버와 데이터베이스를 포함한 전자명함 시스템으로 일대다 또는 다대다로 명함을 교환할 수 있다. NFC 리더기로부터 명함 정보를 수집하고 수집된 명함 정보를 스마트폰 애플리케이션으로 효율적으로 송수신하는 명함 관리 시스템을 구현하였다. 시스템은 데이터전송 과정에서 개인정보 유출을 방지하기 위해 보안성을 제공하고 애플리케이션과 함께 명함정보를 효율적으로 관리한다.

• Journal of Communications and Networks
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• 제9권3호
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• pp.296-311
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• 2007

Mobile multi-robot teams are useful in many critical applications such as search and rescue. Explicit communication among robots in such mobile multi-robot teams is useful for the coordination of such teams as well as exchanging data. Since many applications for mobile robots involve scenarios in which communication infrastructure may be damaged or unavailable, mobile robot teams frequently need to communicate with each other via ad hoc networking. In such scenarios, low-overhead and energy-efficient routing protocols for delivering messages among robots are a key requirement. Two important primitives for communication are essential for enabling a wide variety of mobile robot applications. First, unicast communication (between two robots) needs to be provided to enable coordination and data exchange. Second, in many applications, group communication is required for flexible control, organization, and management of the mobile robots. Multicast provides a bandwidth-efficient communication method between a source and a group of robots. In this paper, we first propose and evaluate two unicast routing protocols tailored for use in ad hoc networks formed by mobile multi-robot teams: Mobile robot distance vector (MRDV) and mobile robot source routing (MRSR). Both protocols exploit the unique mobility characteristics of mobile robot networks to perform efficient routing. Our simulation study show that both MRDV and MRSR incur lower overhead while operating in mobile robot networks when compared to traditional mobile ad hoc network routing protocols such as DSR and AODV. We then propose and evaluate an efficient multicast protocol mobile robot mesh multicast (MRMM) for deployment in mobile robot networks. MRMM exploits the fact that mobile robots know what velocity they are instructed to move at and for what distance in building a long lifetime sparse mesh for group communication that is more efficient. Our results show that MRMM provides an efficient group communication mechanism that can potentially be used in many mobile robot application scenarios.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.625-626
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• 2008

Today, the railway is very important in modern society means of public transport. Many people use the railway each day. On the other hand, with regard to railway accidents every year due to damage caused many casualties. In this paper, we propose railroad crossing accident prevention system for monitoring the situation based on OSGi for safe railway operations, about the same railroad crossing a dangerous place. This system, communication between the train and railroad crossing. So the information from the train crossing while a train driver was monitored in real time with more information than can help prevent accidents on the crossing. Using the OSGi framework, can be used widely in many hardware.

• 기술사
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• 제42권6호
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• pp.28-30
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• 2009

There is a proverb in Korea "Don't chase after another." It can be a right proverb in sometimes. However, usually it doesn't fit in these various society, information knowledge society. Modern society requires convergence technology. IBS (Intelligent Building System) requires knowledge of architecture field, electric field, communication field, and computation field. ITS (Intelligent Transport Systems) which is constructing in many cities requires various knowledge as engineering works, electricity, computation, communication and transportation. In the case of u-City, it requires technology of many fields as architecture, electricity, communication, engineering works, transportation, and computation. Anyone who wants to participate in u-City should study and acquire knowledge in various field. Otherwise, it must be failed because of lack of communication like as the Tower of Babel. U-City is not a portion of one field. Therefore, engineers in many fields should cooperate with each other to make u-city as the best product in the world.

• International Journal of Contents
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• 제2권1호
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• pp.9-16
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• 2006

Recently many researches are investigating for ubiquitous computing and network. In the real world many sensor devices must be equipped to provide many services for users. To make computing environment easy and more user friendly, middleware system not only hides all complexities (network, system, services, etc), but also needs to have efficient context inference scheme and system reconfiguration capability. In this paper we suggest context-aware middleware design for sensor network which provides efficient computing environment for end-users. We also present XML based implementation of our system.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.705-708
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• 2001

최근 카오스현상에 대한 연구가 지속적으로 이루어지고 있다. 카오스 현상을 이용하여 많은 분야에서 다양하게 연구되고 많은 응용기술이 개발되고 있다. 본 논문에서는 1차원 CNN을 구성하여 하이퍼카오스 신호를 생성하고 하이퍼카오스 동기화 구현하는데 초점을 맞추었다.

• Journal of Information Technology Applications and Management
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• 제9권1호
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• pp.61-70
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• 2002

There are a lot of shopping malls in Internet and most of consumers want to buy good goods in cheap price through the shopping malls. To support them, many sites for price comparison are constructed. But man or woman search many shopping malls and insert their price informations into database that the price comparison sites own. To overcome this disadvantage, virtual shopping malls are builded. These virtual shopping malls are connected and cooperated a lot of affiliated existing shopping malls for the cheapest price information. But, these virtual shopping mall are connected to those existing shopping malls in synchronous. So If they are connected to many existing shopping malls, we have to wait long time because of searching for many existing shopping malls. In this paper, we designed and implemented a virtual shopping mall that connect to many existing shopping malls in asynchronous. For a asynchronous communication between this virtual shopping mall and many existing shopping malls, we used JMS (Java Message Service) that is a standard Java API for MOM (Message-Oriented Middleware).