• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.49-55
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• 2018

In this paper, we propose schemes of blockchain utilization in tactical communication environment. The military tactical communication environment has similar characteristics with blockchain network such as distributed architecture, decentralization, and the need for data integrity. A communication node constituting a tactical communication network is constituted by a system capable of configuring and connecting a network for each node. When a communication node, having such capabilities, is configured as a node of blockchain network, various functions could be performed. In this paper, we propose utilization schemes of authentication, integrity, record management, and privilege control based blockchain technology. Functions for authentication, integrity verification, and record management need to ensure the stored data and could track history. The requirement of function's characteristics are matched to blockchain which is storing data sequentially and difficult to hack data, so that it could perform functionally and sufficiently well. Functions for authority control should be able to assign different privileges according to the state of the requestor. Smart contract will function when certain conditions are satisfied and it will be able to perform its functions by using it. In this paper, we will look over functions and utilization schemes of blockchain technology which could reliably share and synchronize data in a tactical communication environment composed of distributed network environment.

• Journal of Korea Multimedia Society
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• v.24 no.11
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• pp.1526-1537
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• 2021

Due to the difference between the underwater communication environment and the terrestrial communication environment, the radio communication mainly used on the ground cannot be used in underwater. For this reason, in the underwater communication environment, various communication media such as acoustic waves, infrared rays, light and so on has been studied, but there exist several difficulties in operating them individually due to their physical limitations. The concept for overcoming these difficulties is the very underwater multi-media communication, a method to select a communication medium best suitable for the current underwater environment among underwater communication multimedia whenever there occurs underwater communication failure. In this paper, we present an underwater multi-media communication network based on star topology and a fragmentation and reassembly technique to solve the problems caused by the different MTU (Maximum Transmission Unit) sizes among different underwater communication media. We also present the estimations and analysis on processing times in each of fragmentation and reassembly and the total data amount for transmitting fragments in our proposed underwater multi-media communication network.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.167-172
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• 2013

Recently, mobile communication systems are suffering from exponentially increasing data traffic. As a promising solution to the increase in data traffic, a coordinated multi-point transmission and reception (CoMP) scheme has been proposed. Although a great deal of research has been done on this new technology, the performance of mobile communication systems with CoMP has not been evaluated properly in a typical indoor environment. To address this, we have developed a system-level simulator and evaluated the performance of mobile communication systems with CoMP. Unlike previous works, we have used an actual antenna pattern in our simulator and link-level results are properly taken into account through link-level abstraction. By using a system-level simulator, we have evaluated the performance of mobile communication systems with CoMP in an indoor environment and found that unlike an outdoor cellular environment, CoMP may not improve the performance of overall mobile communication systems in an indoor environment.

• The Korean Journal of Community Living Science
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• v.22 no.1
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• pp.21-33
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• 2011

This study examined the effects of family environmental variables and parent-child communication on the self-esteem of delinquent and non-delinquent juveniles. For this study, a questionnaire was administered to 117 non-delinquent juveniles living with their parents as high school students and 98 delinquent juveniles aged 15~18 who live in detention centers for adolescence. The data was analyzed using t-test, cross-tab, correlation, and hierarchical multiple regression analysis with SPSS /PC window program. Based on these results, the following conclusions were drawn. First, it was found that non-delinquent juveniles show a more open communication style with their parents than delinquent juveniles. Furthermore, a high level of parent-child communication was associated with high self-esteem in adolescents. Second, although physical environment such as family type or economic status influences an adolescents' self-esteem, the degree of positive parent-child communication style has a much greater effect on an adolescents' self-esteem. Finally, in terms of the effects of family environmental variables and parent-child communication style on self-esteem, parent-child communication style has a stronger effect on delinquent juveniles than non-delinquent juveniles. These results shows the importance of communication style between parent and child, especially for families with delinquent juveniles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.3
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• pp.911-931
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• 2021

Recently, most cloud services use Docker container environment to provide their services. However, there are no researches to evaluate the performance of communication libraries for multi-GPU based distributed deep learning in a Docker container environment. In this paper, we propose an efficient communication architecture for multi-GPU based deep learning in a Docker container environment by evaluating the performances of various communication libraries. We compare the performances of the parameter server architecture and the All-reduce architecture, which are typical distributed deep learning architectures. Further, we analyze the performances of two separate multi-GPU resource allocation policies - allocating a single GPU to each Docker container and allocating multiple GPUs to each Docker container. We also experiment with the scalability of collective communication by increasing the number of GPUs from one to four. Through experiments, we compare OpenMPI and MPICH, which are representative open source MPI libraries, and NCCL, which is NVIDIA's collective communication library for the multi-GPU setting. In the parameter server architecture, we show that using CUDA-aware OpenMPI with multi-GPU per Docker container environment reduces communication latency by up to 75%. Also, we show that using NCCL in All-reduce architecture reduces communication latency by up to 93% compared to other libraries.

• Journal of Korean Library and Information Science Society
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• v.38 no.2
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• pp.373-397
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• 2007

The purpose of this paper is to discuss marketing strategies for school library. The writer divided marketing environment of school library into macro-external environment, micro-external environment, substantial environment, and operational environment. And analyzed characteristics of four target audiences-school administrator, teachers, students, and parents and local society-for school library marketing and suggested approach strategies to each target audiences. Four communication strategies of school library media specialist for effective marketing are discussed ; administrative communication, behavioral communication, cooperative communication, and social communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3384-3400
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• 2021

With the advent of the data era, people pay much more attention to data corruption. Aiming at the problem that the majority of existing schemes do not support corruption detection of ciphertext data stored in cloud environment, this paper proposes a data corruption detection scheme based on ciphertexts in cloud environment (DCDC). The scheme is based on the anomaly detection method of Gaussian model. Combined with related statistics knowledge and cryptography knowledge, the encrypted detection index for data corruption and corruption detection threshold for each type of data are constructed in the scheme according to the data labels; moreover, the detection token for data corruption is generated for the data to be detected according to the data labels, and the corruption detection of ciphertext data in cloud storage is realized through corresponding tokens. Security analysis shows that the algorithms in the scheme are semantically secure. Efficiency analysis and simulation results reveal that the scheme shows low computational cost and good application prospect.

• Electronics and Telecommunications Trends
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• v.38 no.4
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• pp.104-115
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• 2023

Communication for multiagent reinforcement learning (MARL) has emerged to promote understanding of an entire environment. Through communication for MARL, agents can cooperate by choosing the best action considering not only their surrounding environment but also the entire environment and other agents. Hence, MARL with communication may outperform conventional MARL. Many communication algorithms have been proposed to support MARL, but current analyses remain insufficient. This paper presents existing communication algorithms for MARL according to various criteria such as communication methods, contents, and restrictions. In addition, we consider several experimental environments that are primarily used to demonstrate the MARL performance enhanced by communication.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.303-309
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• 2013

This paper analyzed about operation environment and policy for US military tactical communication, and security policy and transmission performance of tactical link. It is presented operation communication message and framework, which is supported semi automated force, SINCGARS specification of link layer in operation environment, and analyzed COMSEC policy and application layer security in tactical security policy. Also it analyzed in respect to transmission performance and crypto synchronization detection. Security policy of tactical link and COMSEC is analyzed in respect of crypto device such as AFKDMS, AKMS, RBECS, KIV-7/HSB.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.181-187
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• 2012

In satellite communication system, propagation characteristics analysis of the receiving environment is very important, because radio quality is changed by the receiving environment. Unlike Terrestrial wireless communications, satellite communication is affected by altitude and atmospheric environment. Therefore, there are many factors to consider for propagation characteristics analysis. In this paper, signal reception environment of geostationary earth orbit was analyzed on urban environment. In order to analyze the propagation simulation, virtual buildings was established and reception environment was changed. The results of this paper would help to design the satellite mobile communication systems in Ka-band.