• Convergence Security Journal
• /
• v.18 no.5_1
• /
• pp.53-58
• /
• 2018

MANET transmits data by hop-by-hop method because it is composed of mobile nodes without support of any infrastructure. Its structure is very similar to a block chain. However, it is exposed to various threats such as data tampering or destruction by malicious nodes because of transmission method. So, ensuring the integrity of transmitted data is an important complement to MANET. In this paper, we propose a method to apply the block chain technique in order to protect the reliability value of the nodes consisting the network from malicious nodes. For this, hierarchical structure of a cluster type is used. Only cluster head stores the reliability information of the nodes in a block and then, this can be spread. In addition, we applied block generation difficulty automatic setting technique using the number of nodes selecting cluster head and the reliability of cluster head to prevent the spread of wrong blocks. This can prevent block generation and spread by malicious nodes. The superior performance of the proposed technique can be verified by comparing experiments with the SAODV technique.

• KIISE Transactions on Computing Practices
• /
• v.22 no.10
• /
• pp.488-496
• /
• 2016

In this paper, we introduce a virtual reality interface for scientific visualization applications. Our VR interface is based on an open-source framework called VR Juggler. Although VR Juggler has its own advantages, it lacks some of the important functionalities needed for practical applications - event handling, synchronization and data sharing among cluster nodes, to name a few. We explain how these issues are resolved while developing the VR interface. Also, a new interface with a smart device, which replaces the virtual reality input device, is introduced. Finally, system usability test results are provided to prove the effectiveness of the proposed interfaces.

• Journal of Internet Computing and Services
• /
• v.10 no.3
• /
• pp.141-150
• /
• 2009

XML is increasingly important in data exchange and information management. A large amount of efforts have been spent in developing efficient techniques for accessing, querying, and storing XML documents. In this paper, we propose a new method to cluster XML documents efficiently. A new prepresentative path called a virtul path which can represent both the structure and the contents of a XML document is proposed for the feature of a XML document. A method to apply the well known hierarchical clustering techniques to the representative paths to cluster XML documents is also proposed. The experiment shows that the true clusters are formed in a compact shape when a virtual path is used for the feature of a XML document.

• Journal of Information Processing Systems
• /
• v.5 no.2
• /
• pp.69-76
• /
• 2009

Self healing systems are considered as cognation-enabled sub form of fault tolerance system. But our experiments that we report in this paper show that self healing systems can be used for performance optimization, configuration management, access control management and bunch of other functions. The exponential complexity that results from interaction between autonomic systems and users (software and human users) has hindered the deployment and user of intelligent systems for a while now. We show that if that exceptional complexity is converted into self-growing knowledge (policies in our case), can make up for initial development cost of building an intelligent system. In this paper, we report the application of AHSEN (Autonomic Healing-based Self management Engine) to in OKKAM Project infrastructure backbone cluster that mimics the web service based architecture of u-Zone gateway infrastructure. The 'blind' load division on per-request bases is not optimal for distributed and performance hungry infrastructure such as OKKAM. The approach adopted assesses the active threads on the virtual machine and does resource estimates for active processes. The availability of a certain server is represented through worker modules at load server. Our simulation results on the OKKAM infrastructure show that the self healing significantly improves the performance and clearly demarcates the logical ambiguities in contemporary designs of self healing infrastructures proposed for large scale computing infrastructures.

• Journal of KIISE:Computer Systems and Theory
• /
• v.32 no.11_12
• /
• pp.557-565
• /
• 2005

This paper presents the development and implementation of a zero-copy file transfer mechanism that improves the efficiency of file transfers for PC cluster systems using hardware-based VIA(Virtual Interface Architecture) network adapters. VIA is one of the representative user-level communication interfaces, but because there is no library for file transfer, one copy occurs between kernel buffer and user boilers. Our mechanism presents a file transfer primitive that does not require the file system to be modified and allows the NIC to transfer data from the kernel buffer to the remote node directly without copying. To do this, we have developed a hardware-based VIA network adapter, which supports the PCI 64bit/66MHz bus and Gigabit Ethernet, as a NIC, and implemented a zero-copy file transfer mechanism. The experimental results show that the overhead of data coy and context switching in the sender is greatly reduced and the CPU utilization of the sender is reduced to $30\%\~40\%$ of the VIA send/receive mechanism. We demonstrate the performance of the zero-copy file transfer mechanism experimentally. and compare the results with those from existing file transfer mechanisms.

• Journal of Fashion Business
• /
• v.13 no.6
• /
• pp.137-146
• /
• 2009

This study analyzed hierarchy of image for visual evaluation of flare skirt. This study analyzed expression words about flare skirt with frequency data of image expression words with different length and volume of flare. Stimuli for the study were set to be 4 different volume of flare ($90^{\circ}$, $180^{\circ}$, $270^{\circ}$, $360^{\circ}$) and 3 different length of skirt(48cm, 58cm, 68cm). Stimuli were made by using I-Designer which is Virtual Sewing System. From simulation of flare skirt, the subjects were asked to write down suggested adjective freely and selected 210 adjectives. With this, we chose total 38 adjectives considering frequencies in the pre-study. And we analyzed the combination process of expression words according to construction factor of flare skirt and hierarchy of image from dendrogram which was resulted by hierarchical cluster analysis. 'Feminine' got high score in all 12 flare skirt. When the skirt was short, it was vivid, and as the skirt got longer, ordinary and pure image showed. Also, as the volume of flare got larger, the average of visual effect was higher than visual image. Visual hierarchy construction according to construction factors of flare skirt could be divided into visual image and visual effect, and visual image was shown to be form 'A type - large volume of flare and short skirt length', 'H type-small volume of flare and short skirt length' and 'X type - large volume of flare and long skirt length'.

• Journal of the Korean Home Economics Association
• /
• v.46 no.2
• /
• pp.73-83
• /
• 2008

The focus of this research was concerned with studying lower body type for Korean adult females. information from the measuring values based on research on the physical standard of the nation(2004) were summarized, in addition a factor of the need for appropriate fit in boots cut jean wear, basic lower body part applying to each item had to be taken into consideration to enhance sizing suitability. The body type are classified into three kinds by means of factor analysis and cluster analysis. Type 1 referred to the fat lower body, having thick rounding waist. compared to other body parts, and long leg according to its proportion. Type 2 represented medium stature but with a large skeleton structure of lower body. Type 3 represented a the long lower body having slender rounding waist. This study was attempted to evaluate the fitness of boots cut jeans pattern for women using 3D Clothes Modeling Software.

• The Journal of the Korea Contents Association
• /
• v.8 no.1
• /
• pp.160-168
• /
• 2008

We completed a new cluster system based on WDM by proposing virtual topology reconfiguration schemes. The key idea of the proposed scheme Is to construct a set with the longest chains of requests of connecting nodes which need to be assigned a wavelength. All the sets have no common factor, that is, there is no duplicated link among the requests of connecting. After making the set satisfying this condition, we could assign a wavelength to per corresponding set. We could reconfigure a virtual topology with this scheme collectively. we compared our scheme to existing approaches by the OWns simulation tool. As the results, we gained improved performances, reducing 10% of blocking rate and improving 30% of ADM utilization in terms of the blocking probability and the ADM utilization.

• Journal of KIISE:Computer Systems and Theory
• /
• v.29 no.12
• /
• pp.648-654
• /
• 2002

The Virtual Interface Architecture(VIA) is an industry standard for communication over system area networks(SANs). M-VIA is a software implementation of VIA technology on Linux. In this paper, we implemented the M-VIA on an AceNIC Gigabit Ethernet by developing a new AceNIC driver for the M-VIA. We analyzed the M-VIA data segmentation processes. When a Gigabit Ethernet MTU is larger than 1514 bytes, M-VIA data segmentation size leaves much room for improvement. So we experimented with various MTU and M-VIA data segmentation size and compared the performances.

• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.299-310
• /
• 2001

In this paper, we study the methodology of distributing the requests of clients based on the state of real server in the LVS(Linux virtual server) clustering system. The WLC(weighted least connection) algorithm in the LVS cluster system is studied. The load distributing algorithm which assigns a weight into each real server is devised by considering the load of real servers. The load test is executed to estimate the load of real servers using a load generating tool. Throughout the result of the experiment, we suggest new load distributing algorithm based on the usage of physical memory of each real server. It is shown that the correction potentiality of new algorithm is somewhat better than that of the WLC algorithm.