• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.99-107
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• 2012

We propose control mechanism of UAV(Unmanned Aerial Vehicle) group for making the communication network to the base station after the target is found. We assume UAVs can communicate to each other by wireless LAN without existing communication infrastructure. UAVs started to fly in linear formation, after finding target, UAVs move to the base station to send the information about the target. At least one UAV stays the position that the target is found. This paper explains the mechanism supporting reliable connectivity during UAV group's flying. We verify the proposed scheme and evaluate the performance through NS-2 simulation. The proposed scheme can be applied to the disaster area and war zone, which the existing communication infrastructure cannot be worked.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.242-258
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• 2015

This study discusses spatial distribution of the silver towns in the Seoul metropolitan area and investigates how the residents recognize their silver towns through in-depth interviews. Nowadays there are many elders who prefer to live in urban downtown or suburb areas which can be connected with the places of their pre-retirement lives. Therefore, the silver towns in the Seoul metropolitan area have been increasing. The facilities are mainly located in northern part of Seoul and southern part of Gyeonggi province near the network of major express roads. Location and accessibility are more important than any other factors when the elderly contemplate moving into silver town. Silver town residents are likely to have meaningful times and positive identities by communicating with friends there. The elders aged 80 years or older living in silver towns think the silver towns as their home while 'young old' people complain their limited rights of decision making and they consider additional move.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.122-123
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• 2018

The purpose of this study is to investigate the problem of installing VR theme park in Korea and to find a solution for it. VR is expected to play a leading role in the fourth industrial revolution as a new industry, but it is a reality that it is hard to feel its value in actual field. This is a reality that can not move one step further because it is trapped in the existing legal network rather than the essence of VR because it sees VR from the existing law frame. Because VR is regarded as an amusement device in the amusement facility and is regarded as a game, the former is applied to the Tourism Promotion Law and the latter is applied to the game industry law. When one content and hardware are applied to both laws at the same time and other regulations are applied to it, it is practically impossible to operate VR properly. In order to solve this problem, it is necessary to revise each law little by little in each law and amend the law that can apply VR itself. This study is expected to contribute to the revitalization of VR industry by presenting the ultimate problems and solutions in creating VR theme parks in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.27-34
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• 2010

As VoIP systems move to wireless environments with much higher average packet loss rates than wired networks, it becomes less possible for the network to assure a reasonable QoS. So, real-time quality monitoring for mobile VoIP applications is an important issue to be explored. In this paper, we explore perceptual quality dependency on two parameters: the burst loss rate and average burst length. Also, we propose a simple 'moving average' approach with $\alpha$ aiming to measure those parameters on real-time basis. In order to find how accurately the two parameters measured estimate the real perceptual quality, we compare actual measured PESQ scores with estimated value by matching the measured quality metric to the trained MOS table. Finally, we propose the quality-based accounting system, which can set obvious continuities between quality and billing.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.208-221
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• 2019

The inference for this research was concentrated on client's data protection in cloud computing i.e. data storages protection problems and how to limit unauthenticated access to info by developing access control model then accessible preparations were introduce after that an access control model was recommend. Cloud computing might refer as technology base on internet, having share, adaptable authority that might be utilized as organization by clients. Compositely cloud computing is software's and hardware's are conveying by internet as a service. It is a remarkable technology get well known because of minimal efforts, adaptability and versatility according to client's necessity. Regardless its prevalence large administration, propositions are reluctant to proceed onward cloud computing because of protection problems, particularly client's info protection. Management have communicated worries overs info protection as their classified and delicate info should be put away by specialist management at any areas all around. Several access models were accessible, yet those models do not satisfy the protection obligations as per services producers and cloud is always under assaults of hackers and data integrity, accessibility and protection were traded off. This research presented a model keep in aspect the requirement of services producers that upgrading the info protection in items of integrity, accessibility and security. The developed model helped the reluctant clients to effectively choosing to move on cloud while considerate the uncertainty related with cloud computing.

• Journal of Communications and Networks
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• v.9 no.3
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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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.335-338
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• 2017

Presently, the collaboration hardware system and software technology that promoted commercializing ICBMS for integrated system visibility evaluation. This variation will move on the next pervasive period that mixed with cultural and technology convergence. There is possibility for the period system can invoke unpredictable confusing blank state. The blank state systems have ecosystem characteristics that are supplied, maintained and operated through the complex interactions of technology and culture. Using universal middleware can support the life-cycle model and increase the visibility of complex systems and prepare for confusing situations. In this study, based on universal middleware, data and service dynamic standardized modules were evaluated to support stable system visibility platform. The system visibility module consists of Intelligent Pervasive Cloud module, Memorial Service module and Life Cycler connection module. each module reflects various requirements of system visibility requested by external system. In addition, the analysis results are supported by various network application service standards through platform independent system and architecture.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.328-334
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• 2004

Recently, Software DSMs continue to improve its performance and scalability As Software DSMs become attractive on larger clusters, the focus of attention is likely to move toward improving the reliability of a system. A popular approach to tolerate failures is message logging with checkpointing, and so many log-based rollback recovery schemes have been proposed. In this work, we propose a remote logging scheme which uses the volatile memory of a remote node assigned to each node. As our remote logging does not incur frequent disk accesses during failure-free execution, its logging overhead is not significant especially over high-speed communication network. The remote logging tolerates multiple failures if the backup nodes of failed nodes are alive. It makes the reliability of DSMs grow much higher. We have designed and implemented the FT-KDSM(Fault Tolerant KAIST DSM) with the remote logging and showed the logging overhead and the recovery time.

• Journal of KIISE:Information Networking
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• v.36 no.4
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• pp.322-329
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• 2009

Many researches in wireless sensor networks have used a geographic routing to effectively disseminate data between sinks and sources. To know the location information, the geographic routing has proposed two manners. A sink-initiated and a source-initiated are flooding to disseminate its location information in WSN. However, these two manners have two problems. Firstly, whenever they move, they flood their location information. Secondly, their location information is disseminated unnecessary nodes besides nodes which send and receive data in actually. Therefore, this paper proposes a protocol that can solve the two problems and disseminate effectively data between few sinks and few sources. The proposed protocol exploits a location information manager that manages location information of the sinks and the sources. We also compare the performance of the proposed protocol with the existing protocols through a simulation.

• Journal of IKEEE
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• v.22 no.4
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• pp.896-900
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• 2018

Traditionally, Linear Shift Feedback Register (LFSR) has been widely employed to implement Cyclic Redundant Check (CRC) codes for a serial input. Since many applications including network and storage systems demand as high throughput as ever, various efforts have been made to implement CRC hardware to support parallel inputs. Among various parallel schemes, the look-ahead scheme is one of the most widely used schemes due to its short critical path. However, it is very cumbersome to design HDL codes for parallel CRC codes since the look-ahead scheme is inevitable to consider how register and input values move in the next cycles. Thus, this paper proposes a novel CRC hardware generator, which automatically produces HDL codes given a CRC polynomial and parallel factor. The experimental results verify the applicability to use the proposed generator by analyzing the synthesis results from the generated HDL code.