• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3224-3242
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• 2020

Internet of Things (IoT) networks composed of a large number of sensors and actuators generate a huge volume of data and control commands, which should be enforced by strong data reliability. The end-to-end data reliability of IoT networks is an essential industrial enabler. Blockchain technology can provide strong data reliability and integrity within IoT networks. We designed a lightweight end-to-end blockchain network that applies to common IoT applications. Its enhanced modular architecture and lightweight consensus mechanism guarantee its practical applicability for general IoT applications. In addition, the proposed blockchain network is highly software compatible because it adopts the Hyperledger development environment. Directly embedding the proposed blockchain middleware platform in small computing devices proves its practicability.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.2
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• pp.75-82
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• 2007

Wireless Sensor Network(WSN) is composed of a large number of sensor nodes and accomplish a common task such as environment monitoring or asset tracking. This paper proposed a congestion control mechanism applying the ECN mechanism and the cross layer design to cope with temporal congestion in WSN. We experimented with the proposed congestion control mechanism using ns-2 simulator and measured the throughput of sink node. Simulation results show that the suggested mechanism can improve the performance of packet throughput by dealing with the congestion of network efficiently.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.161-168
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• 2023

It is a common practice to use a password in order to restrict access to information, or in a general sense, to assets. Right selection of the password is necessary for protecting the assets more effectively. Password finding/cracking try outs are performed for deciding which level of protection do used or prospective passwords offer, and password cracking algorithms are generated. These algorithms are becoming more intelligent and succeed in finding more number of passwords in less tries and in a shorter duration. In this study, the performances of possible password finding algorithms are measured, and a hybrid algorithm based on the performances of different password cracking algorithms is generated, and it is demonstrated that the performance of the hybrid algorithm is superior to the base algorithms.

• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.44-48
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• 2023

Augmented Reality (AR) is an emerging technology and a vibrant field, it has become common in application development, especially in smartphone applications (mobile phones). The AR technology has grown increasingly during the past decade in many fields. Therefore, it is necessary to determine the optimal approach to building the final product by evaluating the performance of each of them separately at a specific task. In this work we evaluated overall CPU and RAM performance for several types of Markerless Augmented Reality applications by using a multiple-objects in mobile development. The results obtained are show that the objects with fewer number of vertices performs steady and not oscillating. Object was superior to the rest of the others is sphere, which is performs better values when processed, its values closer to the minimum CPU and RAM usage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.2
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• pp.115-127
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• 1991

In this paper. we dIscussed wIth the ISDN numberIng system of Korea 2digIt of NDC(National Destination Code)is assigned to the common carrier indenttification and an other the service network identification code as conbining the flIst and second dIgIt. The last ot NDC is applicable to for each area code. Resulty. we become 10 digit number for toll system vice 7 digit for local numbering. It is satisfactory to CCITT recommandtion and also. We has been suggested that existing network the mobile. pagget, FAX, TELEX and public networks are able to be connetcted to the ISDN. Near the 1994. we guess that it is fully occupied with 7 digit number to the metropolitan area to solve this problem, after divide to 3 part provincial area southern. nothem and mid-Korea. We suggested that special number system are reorganized with the new and existing service numbers plan. Although, we don't deal with the SA of ISDN numbering systems. Resultly, know that we are to design efficiently number system as 3 digit code for ISDN/NSN.

• Korean Journal of Social Welfare Studies
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• v.41 no.4
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• pp.313-343
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• 2010

The aim of this study is to examine the factors influencing network centrality on women's welfare organizations, and to investigate how the level of network centrality influence the effectiveness of the organization. To achieve this goal, this study conducted a survey on women's welfare organizations in Seoul from March to June, 2009. Network analysis method was used to get each organization's network centrality value. Also, through the Structural Equation Modelling, organizational characteristics predicting network centrality and effect of network centrality on organizational effectiveness. The main results are as follows. First, the significant affecting factors were different between three types of centralities with regards to the type of organization, recognition of resource dependency, attitude of top manager, and established year. Second, the common factors affecting three network centralities were the number of informal ties, accepting feminism as the main organizational philosophy, and the number of qualified staffs. Third, only closeness centrality positively predicted the level of organizational effectiveness among three types of centralities. The faster the organization reaches to other organizations in a network, the organizational effectiveness becomes higher, which means high closeness centrality is more important factor than high degree centrality or high betweenness centrality to increase organizational effectiveness. This result shows social welfare organization should consider changing inter-organizational network strategy from quantity-focused to quality-focused.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.802-812
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• 2000

Multihop lightwave networks are the optical-fiber based local communication systems that employ WDM(Wavelength Division Multiplexing) technology to fully use the enormous fiber bandwidth without requiring any tunable tranceives. In this paper, we introduce a novel ShuffleNet topology, asymmetric bilayered ShuffleNet(ABS) topology as a multihop WDM network technique. For 1Gb/s transmission system, we compared ABS topology with previously reported ones in terms of common network parameters such as average number of hops, throughput, time delay, and network power function. Through the analysis, the performance of ABS topology was proven to be superior to the existing ones. To decrease the amount of hardware required for implementing ABS system, we also proposed a new WDM channel sharing scheme. For (2, 3) ShuffleNet topology system, the number of wavelengths needed in the system can be reduced dramatically from 96 to 4 by using new scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.11
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• pp.2365-2374
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• 1997

This paper describes two algorithms for technology mapping of multiple output functions into interesting and pupular FPGAs(Field Programmable Gate Array) that use look-yp table memories. For improvement of technology mapping for FPGA, we use the functional decompoition method for multiple output functions. Two algorithms are proposed. The one is the Roth-Karpalgorithm extended for multiple output functions. The other is the efficient algorithm which looks for common decomposition functions through the decomposition procedure. The cost function is used to minimize the number of CLBs and nets and to improve performance of the network. Finally we compare our new algorithm with previous logic design technique. Experimental resutls show sigificant reduction in the number of CLBs and nets.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.379-388
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• 2007

With proliferation of computer and wireless network technology, it is common to access Internet through wireless network using mobile device. Ratio of using streaming media out of many applications through Internet is increasing not only in wired network but also in wireless network. Streaming media is much bigger than other contents and requires more network bandwidth and more computing resources. However mobile devices hate relatively poor computing resource and low network bandwidth. If media streaming service is provided for mobile devices without any consideration about network bandwidth and computing power, it is hard for the client to get high qualify service. Since mobile device is supported with very limited energy from the battery, media streaming should be adjusted to varying energy state of mobile device in realtime to ensure complete playback of streaming media. In this paper, we propose DFRC to provide high qualify service to mobile client through wireless network by controlling the number of frames transmitted to client based on computing resource and energy state of mobile device.

• Journal of the Korean Professional Engineers Association
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• v.28 no.3
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• pp.121-134
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• 1995

To operate the automatic devices of manufacturing process more effectively and to solve the needs of the resource sharing, network technology is applied to the unit con-trol devices located In common manufacturing zone and operated by connecting them. The network management system, which controls and supervises the network resources in the communication network, is the function that is necessarily required in this net-work. For the stability in this network, this paper measures the variation of data packet length and node number and analyzes the variated value of the token rotation time and waiting time for the network operation. On the evalution of the performance, the data packet length varies from 10 bytes to 100 bytes in the operation of the group manage-ment network, the variation of the token rotation time and waiting time is less than 10 msec. When the variation of the data packet lenhth is less than 50 bytes, differences in token rotation time or waiting time is unnoticable. Since the waiting time in this case is less than 10 msec, response time Is fast enough.