• Journal of KIISE:Computing Practices and Letters
• /
• v.7 no.2
• /
• pp.109-120
• /
• 2001

In this paper, we propose the design and implementation of a portable, extensible, and efficient performance visualization framework for high performance parallel program development. The framework adopts a layered architecture:consists of three independent layers instrumentation layer, trace interface layer and visualization layer. The instrumentation layer was constructed as an ECL which captures generated events, and the EDL/JPAL constitutes the trace interface layer to provide problem-oriented interfaces between visualization layer and instrumentation layer. Finally, the visualization layer was designed as plug-and-play style for easy elimination, addition and composition of various filters, views and view groups, The proposed performance visualization framework is expected to be used as an independent performance debugging and analysis tool and as a core component in an integrated parallel programming environment.

• The KIPS Transactions:PartA
• /
• v.10A no.4
• /
• pp.279-284
• /
• 2003

In this paper, we propose an efficient architecture for radix-4 modular multiplication in systolic array structure based on the Montgomery's algorithm. We propose a radix-4 modular multiplication algorithm to reduce the number of iterations, so that it takes (3/2)n+2 clock cycles to complete an n-bit modular multiplication. Since we can interleave two consecutive modular multiplications for 100% hardware utilization and can start the next multiplication at the earliest possible moment, it takes about only n/2 clock cycles to complete one modular multiplication in the average. The proposed architecture is quite regular and scalable due to the systolic array structure so that it fits in a VLSI implementation. Compared to conventional approaches, the proposed architecture shows shorter period to complete a modular multiplication while requiring relatively less hardware resources.

• Journal of KIISE:Databases
• /
• v.33 no.4
• /
• pp.423-436
• /
• 2006

In recent years, publish-subscribe (pub-sub) systems based on XML document filtering have received much attention. In a typical pub-sub system, subscribing users specify their interest in profiles expressed in the XPath language, and each new content is matched against the user profiles so that the content is delivered only to the interested subscribers. As the number of subscribed users and their profiles can grow very large, the scalability of the system is critical to the success of pub-sub services. In this paper, we propose a novel scalable filtering system called FiST(Filtering by Sequencing Twigs) that transforms twig patterns expressed in XPath and XML documents into sequences using Prufer's method. As a consequence, instead of matching linear paths of twig patterns individually and merging the matches during post-processing, FiST performs holistic matching of twig patterns with incoming documents. FiST organizes the sequences into a dynamic hash based index for efficient filtering. We demonstrate that our holistic matching approach yields lower filtering cost and good scalability under various situations.

• Journal of Digital Convergence
• /
• v.12 no.5
• /
• pp.1-12
• /
• 2014

Recently, the need for non-stop service is increasing by the business mission-critical Internet banking, e-payment, e-commerce, home shopping, securities trading, and petition business increases, clustered in a single database of existing, redundant research on high-availability technologies related to technique, etc. is increasing. It provides an API based on the Active Log in addition to the technique of redundancy, ALTIBASE$^{TM}$ Log Analyzer (below, ALA), provides scalability and communication of the same model or between heterogeneous. In this paper, we evaluated the performance of ALA by presenting the design of the database system that you can use the ALA, to satisfy all the synchronization features high scalability and high availability, real-time.

• Journal of Digital Convergence
• /
• v.18 no.3
• /
• pp.171-177
• /
• 2020

Under the influence of the Fourth Industrial Revolution, there are many tries to promote productivity enhancement and competitiveness by adapting smart farm technology that converges ICT technologies in agriculture. This smart farming technology is emerging as a new paradigm for future growth in agriculture. The development of real-time cultivation environment monitoring and automatic control system is needed to implement smart farm. Furthermore, the development of intelligent system that manages cultivation environment using monitoring data of the growth of crops is required. In this paper, a fast and efficient development method for implementing a cloud-based smart farm management system using a highly compatible and scalable web platform is proposed. It was verified that the proposed method using the web platform is effective and stable system implementation through the operation of the actual implementation system.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.4
• /
• pp.67-75
• /
• 2009

Multi-layered video coding that provides scalability across the visual content has emerged for easily adaptive service over current heterogeneous network. However, the network is still error prone environment so that video service may suffer packet loss or erroneous decoding of the video. Especially distortion caused by the burst error may propagate to several pictures until intra refreshing, which will raise a terrific degradation of picture quality. To overcome the problem at terminal independently, we propose a new error concealment algorithm for the multi-layered video coding. The proposed method uses the similarity of between layers in the multi-layered video coding and POCS (Projections Onto Convex Sets) which is a powerful error concealment tool, but heavily dependent on initial values. To find adequate initial value which can reduce iteration times as well as achieve high performance, we took consideration into both features of layered approach coding and the correlation in neighbor blocks. The simulation results show that the proposed concealment method works well.

• Journal of Communications and Networks
• /
• v.10 no.4
• /
• pp.455-464
• /
• 2008

To provide network services consistently under various network failures, enterprise networks increasingly utilize path diversity through multi-homing. As a result, multi-homed non-transit autonomous systems become to surpass single-homed networks in number. In this paper, we address an inevitable problem that occurs when networks with multiple entry points deploy firewalls in their borders. The majority of today's firewalls use stateful inspection that exploits connection state for fine-grained control. However, stateful inspection has a topological restriction such that outgoing and incoming traffic of a connection should pass through a single firewall to execute desired packet filtering operation. Multi-homed networking environments suffer from this restriction and BGP policies provide only coarse control over communication paths. Due to these features and the characteristics of datagram routing, there exists a real possibility of asymmetric routing. This mismatch between the exit and entry firewalls for a connection causes connection establishment failures. In this paper, we formulate this phenomenon into a state-sharing problem among multiple fire walls under asymmetric routing condition. To solve this problem, we propose a stateful inspection protocol that requires very low processing and messaging overhead. Our protocol consists of the following two phases: 1) Generation of a TCP SYN cookie marked with the firewall identification number upon a SYN packet arrival, and 2) state sharing triggered by a SYN/ACK packet arrival in the absence of the trail of its initial SYN packet. We demonstrate that our protocol is scalable, robust, and simple enough to be deployed for high speed networks. It also transparently works under any client-server configurations. Last but not least, we present experimental results through a prototype implementation.

• The KIPS Transactions:PartA
• /
• v.14A no.4
• /
• pp.215-226
• /
• 2007

For past years, many distributed virtual shared-memory(DVSM) systems have been studied in order to develop a low-cost shared memory system with a fast interconnection network. But the DVSM needs a lot of data and control communication between distributed processing nodes in order to provide memory consistency in software, and this communication overhead significantly dominates the overall performance. In general, the communication overhead also increases as the number of processing nodes increase, so communication overhead is a very important performance factor for developing a large-scale DVSM system. In this paper, we study the performance scalability quantitatively and qualitatively for developing a large-scale DVSM system based on the next generation interconnection network, called the InfiniBand. Based on the study, we analyze a performance requirement of the next-coming interconnection network to be used for developing a performance-scalable DVSM system in the future.

• The KIPS Transactions:PartA
• /
• v.13A no.3 s.100
• /
• pp.231-240
• /
• 2006

In this paper, wireless internet proxy server clusters are used for the wireless internet because their caching, distillation, and clustering functions are helpful to overcome the limitations and needs of the wireless internet. TranSend was proposed as a clustering based wireless internet proxy server but it has disadvantages; 1) its scalability is difficult to achieve because there is no systematic way to do it and 2) its structure is complex because of the inefficient communication structure among modules. In our former research, we proposed the CD-A structure which can be scalable in a systematic way but it also has disadvantages; its communication structure among modules is partly complex. In this paper, we proposed a consolidated scheme which has a systematic scalability and an efficient communication structure among modules. We performed experiments using 16 PCs and experimental results show 196% and 40% performance improvement of the proposed system compared to the TranSend and the CD-A system, respectively.

• Journal of KIISE:Computer Systems and Theory
• /
• v.30 no.5_6
• /
• pp.239-249
• /
• 2003

The secret sharing is the basic concept of the threshold cryptosystem and has an important position in the modern cryptography. At 1995, Jarecki proposed the proactive secret sharing to be a solution of existing the mobile adversary and also proposed the share renewal scheme for (k, n) threshold scheme. For n participants in the protocol, his method needs $O(n^2)$ modular exponentiation per one participant. It is very high computational cost and is not fit for the scalable cryptosystem. In this paper, we propose the efficient share renewal scheme that need only O(n) modular exponentiation per participant. And we prove our scheme is secure if less than img ${\frac{1}{2}}$ n-1 adversaries exist and they are static adversary.