• KIPS Transactions on Computer and Communication Systems
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• v.5 no.5
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• pp.109-116
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• 2016

Today various IoT platforms exist, but most of them only consider IPv6, without other types of network including private network. They support, therefore, the private network to use virtual private network or through the hardware gateway. To solve this limitation, we propose a IoT platform that provides IoT Services on private networks. Also we verify this platform though constructing a testbed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5425-5448
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• 2018

Wireless sensor network has been widely used in Internet of Things (IoT) applications to support large and dense networks. As sensor nodes are usually tiny and provided with limited hardware resources, the existing multiple access methods, which involve high computational complexity to preserve the protocol performance, is not available under such a scenario. In this paper, we propose an intelligent Medium Access Control (MAC) protocol selection scheme based on machine learning in wireless sensor networks. We jointly consider the impact of inherent behavior and external environments to deal with the application limitation problem of the single type MAC protocol. This scheme can benefit from the combination of the competitive protocols and non-competitive protocols, and help the network nodes to select the MAC protocol that best suits the current network condition. Extensive simulation results validate our work, and it also proven that the accuracy of the proposed MAC protocol selection strategy is higher than the existing work.

• Cartoon and Animation Studies
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• s.20
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• pp.1-14
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• 2010

The success of a three-dimensional blockbuster movie, AVARTA, brought an public attention on the expansion of three-dimensional computer applications, and it allows experts predict further hardware technology developments to support the such applications. Futhermore, an internet based infra structure and three-dimensional structure, third generation network community, advanced computer networks have influenced advancement in computer technology within the 3D game industry and the spread of 2D computer animation technologies. This advancement of computer technologies allow the industry to overcome a limitation of generating cultural design contexts existed within 2D network community. However, despite of the expansion of 2D and 3D computer technologies, a limitation of analysing designers' intentions on morphology of digital contents and user interface still exists. Therefore, the purpose of this study is to analyze (1) present conditions of the 3D industry and (2) protocols of designers' cognitive design processes based on their design communication, contents, and tools. Analysis was conducted based on literature reviews and case precedent analyses. For the analysis, a 2D Avarta sketch character was designed and then applied into a 3D game system. Observations how designers solve cultural problem within the structure via Avarta were conducted. Outcomes were then coded for further analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.12
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• pp.1902-1918
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• 1993

Parallel architecture based on the von Neumann computation model has a limitation as a massively parallel architecture due to its inherent drawback of architectural features. The data-flow model of computation has a high programmability in software perspective and high scalability in hardware perspective. However, the practical programming and experimentaion of date-flow architectures are hardly available due to the absence of practical data-flow, we present a programming environment for performing the data-flow computation on conventional parallel machines in general, loosely compled multiprocessor system in particular. We build an emulator for tagged token data-flow architecture on the iPSC/2 hypercube, a loosely coupled multiprocessor system. The emulator is a shallow layer of software executing on an iPSC/2 system, and thus makes the iPSC/2 system work as a data-flow architecture from the programmer`s viewpoint. We implement various numerical and non-numerical algorithm in a data-flow assembler language, and then compare the performance of the program with those of the versions of conventional C language, Consequently, We verify the effectiveness of this programming environment based on the emulator in experimenting the data-flow computation on a conventional parallel machine.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7A
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• pp.717-723
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• 2007

There are many weaknesses in sensor networks due to hardware limitation of sensor nodes besides the vulnerabilities of a wireless channel. In order to provide sensor networks with security, we should find out the approaches different from ones in existing wireless networks; the security mechanism in sensor network should be light-weighted and not degrade network performance. Sowe proposed a novel data origin authentication satisfying both of being light-weighted and maintaining network performance by using Unique Random Sequence Code. This scheme uses a challenge-response authentication consisting of a query code and a response code. In this paper, we show how to make a Unique Random Sequence Code and how to use it for data origin authentication.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.71-75
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• 2008

Many sensor operating systems have memory limitation constraint; therefore, stack memory areas of threads resides in a single memory space. Because most target platforms do not have hardware MMY (Memory Management Unit), it is difficult to protect each stack area. The method to solve this problem is to exchange original stack handling instructions in binary code for wrapper routines to protect stack area. In this exchanging phase, instruction corruption problem occurs due to difference of each instruction length between stack handling instructions and branch instructions. In this paper, we propose the algorithm to call a target routine without instruction corruption problem. This algorithm can reach a target routine by repeating branch instructions to have a short range. Our solution makes it easy to apply security patch and maintain upgrade of software of sensor node.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.5
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• pp.209-220
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• 2016

While the services of mobile devices like smart phone, tablet, and smart watch have been increased and varied, the software embedded into such devices has been also increased in size and functional complexity. Therefore, increasing operation time of mobile devices for serviceability became an important issue due to the limitation of battery power. Recent studies focus on the software development having efficient behavioral patterns because the energy consumption of mobile devices is caused by software behaviors which control the hardware operations. However, it is often difficult to develop the embedded software with considering energy-efficiency and behavior optimization due to the short development cycle of the mobile services in many cases. Therefore, this paper proposes the refactoring techniques for reducing energy consumption, and enables to fulfill the energy requirements during software development and maintenance. We defined energy bad smells with the code patterns that can excessively consume the energy, and our refactoring techniques are to remove these bad smells. We performed some case studies to verify the usefulness of our refactoring techniques.

• 전자공학회논문지 IE
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• v.43 no.1
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• pp.46-51
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• 2006

Recently, smart card system which is known as easy to portable and also safe from physical, electrical, and software attack is observed to manage information that becomes the target of security in safety. And java card graft upon java technology to smart card platform is having very good advantage with object-oriented techniques and also, java card have the open type OS that can show the same action in different hardware characteristic which allows various application programs. In this paper, we introduced independent execution characteristic of java platform because being set to each smart card was uncomfortable till now and we designed access control member card that allows several administrators in different access privilege by single card using java card. Several administrators can approach to various information of file type that is included on issued card to user by using different PIN. In the proposed method, confirmation of personal information, administration contents update, demand by contents, is possible by single card. At this moment, wish to do safer user certification that improve security limitation which is from PIN, used for user certification, and signature data. In the proposed method, as design and implementation of utilization technology of java card, biometrics, user certification which uses multi PIN, provide that more safety and conveniently.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.4
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• pp.11-17
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• 1980

This paper describes realization of digital filter using $\mu$p controler and discusses measured characteristics of this filter, The idea of P. L. implementation[1] is used in realization, and in this system we utilize a DMA and arithmatic control program of $\mu$p. In this way, we can get more flexible capability than the basic PL method, and higher speed than a filter using general purpose $\mu$p in hardware, Furthermore, we get a 15 KHz sampling frequency(fs) as speed limit in real time processing, and know that this limitation is restricted by execution time (58$\mu$ sec) of DMA control statement. As for filter charateristics, maximum stop band frequencies (fsp) are 1665 Hz, 1445 Hz in Butterworth and Tchebichef approximation, respectively, when fs = 14 KHz. Measured errors between the design specification and the actual result are 0.2dB, 0.1 dB in pass band (when cufoff frequency is 500Hz),-1.1dB (when fsp is 1000Hz), 0.4dB(when fsp is 750 Hz) in stop band frequency of Butterworth and Tchebichef, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.284-290
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• 2016

As the recently advanced scientific developments result in high lever of the usability and the needs for the electrical equipment and devices in various situations, the safety technologies protecting malfunction and electrical critical damages including soft and hardware from the unexpectedly radiated electromagnetic interferences are required gradually. In addition, the numerical analysis for the miniaturized electrical components and equipments as well as the conventional electrical devices installed inside the electrically large enclosures and structures requires the memory requirement and time consumption too big to be handled in a realistic situation, which will result in a limitation in solving the complete set of maxwell's equations. In this paper, PWB method based on statistical theory and topological modeling with appropriate zoning concepts are introduced for the EM analysis of an electrically large complex structures.