• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4203-4223
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• 2021

Accelerated by the Internet of Things (IoT), the need for further technical innovations and developments within wireless communications beyond the fifth generation (B5G) networks is up-and-coming in the past few years. High altitude platform station (HAPS) communication is expected to achieve such high levels that, with high data transfer rates and low latency, millions of devices and applications can work seamlessly. The HAPS has emerged as an indispensable component of next-generations of wireless networks, which will therefore play an important role in promoting massive IoT interconnectivity with 6G. The performance of communication and key technology mainly depend on the characteristic of channel, thus we propose an efficient Markov chain based channel model, then analyze the HAPS communication system's uplink capability and swing effect through experiments. According to the simulation results, the efficacy of the proposed scheme is proven to meet the requirements of ubiquitous connectivity in future IoT enabled by 6G.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.913-922
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• 2006

It used exclusively the radio communication where is the TRS(Trunked Radio Service) at frequency where the person whom it does is specific with hitherto radio communication method differently frequency of the decimal which is allocated to the relay station it talks the at the room which the multiple user uses with commonness. The TRS system the most big feature is the region multiple group and order communication method. The TRS the composition of system is composed of the multi mind group, the each group is composed of the terminal of the users who have the objective which is similar relates in business contents. With above it follows in same multi objective and the connection of the form which is various or group communication accomplishes and quality case, a possibility a or of having many problem point in key distribution for a large scale communication there is it could be exposed to attack of the form which is various. There is a place where it accomplishes the communication which is safe at the TRS from research which it sees it investigates group key distribution method which is an essential element. The method which it sees when it reduces a communication frequency, it stands but is the user, it proposes the efficient group key distribution method it will be able to accomplish.

• The KIPS Transactions:PartC
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• v.14C no.7
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• pp.553-558
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• 2007

In this paper, we introduce a set of structures and algorithms for communication efficient public key revocation in wireless sensor networks. Unlike the traditional networks, wireless sensor network is subjected to resources constraints. Thus, traditional public key revocation mechanisms such like the ordinary certificate revocation list is unsuitable to be used. This unsuitability is due to the huge size of required representation space for the different keys' identifiers and the revocation communication as the set of revoked keys grow. In this work, we introduce two communication-efficient schemes for the certificate revocation. In the first scheme, we utilize the complete subtree mechanism for the identifiers representation which is widely used in the broadcast encryption/user revocation. In the second scheme, we introduce a novel bit vector representation BVS which uses vector of relative identifiers occurrence representation. We introduce different revocation policies and present corresponding modifications of our scheme. Finally, we show how the encoding could reduce the communication overhead as well. Simulation results and comparisons are provided to show the value of our work.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.1
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• pp.70-77
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• 2021

This paper was reclassified industries related to the 4th industrial revolution into manufacturing, information and communication services, finance and insurance services, and science and technology services by comparing the industry association table with the Korean standard industry classification. And the economic ripple effect was analyzed by exogenizing the four sectors of the industry using a demand-driven model. The wholesale and retail and product brokerage services were measured to be large in the manufacturing, information communication services, and science technology service sector according as a result of analysis of the production inducement effect, added value inducement effect, and employment inducement effect. And the financial and insurance services were analyzed to be large in the financial and insurance services sector. The import inducement effect was analyzed to be the largest in all sectors of the fourth industry. As a result of the forward and backward linkage effect, it was confirmed that the manufacturing and the information communication services sector were the intermediate primary production type sensitive to economic fluctuations. Also it was confirmed that the financial and insurance services and the science technology services sector were the final primary production type.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.2
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• pp.29-40
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• 2005

In this research, we propose packet scheduling algorithm considering different QoS characteristics of real-time traffic and non-real-time traffic in the next generation wireless communication system serving the multimedia traffic and a new efficient framing method cooperated with this packet scheduler. When the selected traffic classes of the selected users are transmitted, our proposed framing method can increase the number of serviced traffic classes by mixing the many different traffic classes within one frame considering data rate decided by the allocated AMC (Adaptive Modulation and Coding) option. Using this proposed method, the fairness among the traffic classes can be achieved and the system performance for total throughput and delay can be enhanced. Simulations are performed to analyze the performance of the proposed framing method. Our proposed packet scheduler and framing method will be applied to the next generation multimedia wireless communication system serving many traffic classes.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.3
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• pp.317-324
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• 2009

Tactical Information Communication Network(TICN) uses both a wireless and wired network. To support mobility in battlefield environments, the application of Ad-hoc networking technology to its wireless communication has been examined. However, Ad-hoc network is faced to many security threats due to its intrinsic characteristics. Therefore, to apply the Ad-hoc networking technology to battlefield environments and TICN, an intensive study on security countermeasure must go side by side with the development of enabling technology. In this paper, we suggest an efficient key management scheme for TICN of which the Ad-hoc networking technology is applied.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3109-3120
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• 1996

SDL has been standardized to specify behavioral aspects of communication systems based on the formal description technique, and it is powerful and user friendly in the sense of supporting human communication and understanding, formal analysis andcomparison of behaviors, alternative implementations and design optimization, and its structural decomposition. However, SDL is not sufficient for an efficient handing of entrire system descriptions because the communication systems are generally very complex, and composed from the various interactions among sub-systems. Also, it is very difficult to explicitly verify dynamic views such as liveness and reachability. it leads the demands on analysis scheme to verify dynamic behaviros of specified systems. This paper presents modeling concepts of Petri Nets from SDL and transformation rules to Numerical Petri Nets to provide efficient technqiques for verification of dynamic behaviors, and proposes the reachability garaph that is able to trace all reachable states of a modeled system and reduce an information loss on the reachability tree.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.207-208
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• 2008

In this paper, we propose an efficient algorithm for reducing the complexity of LDPC code decoding by using node monitoring (NM). This NM algorithm is based on a new node-threshold method, and the message passing algorithm. This algorithm was simulated in order to verify its efficiency. Simulation results show that the complexity of our NM algorithm is improved to about 10%, compared with well-known methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.7
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• pp.3648-3663
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• 2017

With the development of cloud computing and widespread availability of mobile devices, outsourcing computation has gotten more and more attention in cloud computing services. The computation of bilinear pairing is the most expensive operation in pair-based cryptographic schemes. Currently, most of the algorithms for outsourcing bilinear pairing have small checkability or the outsourcers need to operate expensive computations. In this paper, we propose an efficient algorithm for outsourcing bilinear pairing with two servers, where the outsourcers can detect the errors with a probability of 1 if the cloud servers are dishonest, and the outsourcers are not involved in any complex computations. Finally, the performance evaluation demonstrates that the proposed algorithm is most efficient in all of fully verifiable outsourcing algorithms for bilinear pairing.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1231-1238
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• 2015

In this paper, we proposed an efficient algorithm using Node monitoring (NM) and Piecewise Linear Function Approximation(: NP) for reducing the complexity of LDPC code decoding. Proposed NM algorithm is based on a new node-threshold method together with message passing algorithm. Piecewise linear function approximation is used to reduce the complexity of the algorithm. This new algorithm was simulated in order to verify its efficiency. Complexity of our new NM algorithm is improved to about 20% compared with well-known methods according to simulation results.