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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The KIPS Transactions:PartA
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Journal DOI :
Korea Information Processing Society
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Volume & Issues
Volume 8A, Issue 4 - Dec 2001
Volume 8A, Issue 3 - Sep 2001
Volume 8A, Issue 2 - Jun 2001
Volume 8A, Issue 1 - Mar 2001
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Design And Implementation of Linux Based Parallel Media Stream Server System
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 287~292
Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.
Double Queue Management for Reducing disk I/O of Web Servers
Yeom, Mi-Ryeong ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 293~298
This paper propose the DoubleQ web server that classifies incoming requests according to whether the requested document is cached or not. Requests that demand a cached document is put into the Service Queue while other requests are added to the Defer Queue. The DoubleQ web server services requests that are in the Service Queue before it services requests in the Defer Queue. This strategy is used to reduce disk accesses that have been the predominant overhead of traditional web servers. Experimental results using synthetic data show that improvements in the average user response time and the throughput of the web server may be achieved.
A study of distributing the load of the LVS clustering system based on the dynamic weight
Kim, Suk-Chan ; Lee, Young ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 299~310
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.
The Design and Implementation of the Multimedia End-to-End Server I/O System based on Linux
Nam, Sang-Jun ; Lee, Byeong-Rae ; Park, Nam-Seop ; Lee, Yun-Jeong ; Kim, Tae-Yun ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 311~318
In recent years, users\` demands for multimedia service are increasing because of a diffusion of internet. Server systems, however, offer inefficient multimedia data service to users. Multimedia applications often transfer the same data between shared devices at very high rates, and therefore require an efficient I/O subsystem. Data copying and context switching have long been identified as sources of I/O inefficiency. Therefore we propose the new Multimedia Stream System Call (MSSC) mechanism, which is inserted into a Linux kernel: The MSSC mechanism operates in kernel domain with RTP (Real-time Transport Protocol). We present measurements indicating that use of our techniques resulted in a 12.5%∼14% gain in throughput as compared with a conventional Linux system.
Transient Overloads Control Mechanism for Virtual Memory System
Go, Yeong-Ung ; Lee, Jae-Yong ; Hong, Cheol-Ho ; Yu, Hyeok ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 319~330
In virtual memory system, when a process attempts to access a page that is not resident in memory, the system generates and handles a page fault that causes unpredictable delay. So virtual memory system is not appropriate for the real-time system, because it can increase the deadline miss ratio of real-time task. In multimedia system, virtual memory system may degrade the QoS(quality of service) of multimedia application. Furthermore, in general-purpose operating system, whenever a new task is dynamically loaded, virtual memory system suffers from extensive page fault that cause transient overloading state. In this paper, we present efficient overloading control mechanism called RBPFH (Rate-Based Page Fault Handling). A significant feature of the RBPFH algorithm is page fault dispersion that keeps page fault ratio from exceeding available bound by monitoring current system resources. Furthermore, whenever the amount of available system resource is changed, the RBPFH algorithm dynamically adjusts the page fault handling rate. The RBPFH algorithm is implemented in the Linux operating system and its performance measured. The results demonstrate RBPFH\`s superior performance in supporting multimedia applications. Experiment result shows that RBPFH could achieve 10%∼20% reduction in deadline miss ratio and 50%∼60% reduction in average delay.
Design and Implementation of a Real Time Access Log for IP Fragmentation Attack Detection
Guk, Gyeong-Hwan ; Lee, Sang-Hun ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 331~338
With the general use of network, cyber terror rages throughout the world. However, IP Fragmentation isn\`t free from its security problem yet, even though it guarantees effective transmission of the IP package in its network environment. Illegal invasion could happen or disturb operation of the system by using attack mechanism such as IP Spoofing, Ping of Death, or ICMP taking advantage of defectiveness, if any, which IP Fragmentation needs improving. Recently, apart from service refusal attack using IP Fragmentation, there arises a problem that it is possible to detour packet filtering equipment or network-based attack detection system using IP Fragmentation. In the paper, we generate the real time access log file to make the system manager help decision support and to make the system manage itself in case that some routers or network-based attack detection systems without packet reassembling function could not detect or suspend illegal invasion with divided datagrams of the packet. Through the implementation of the self-managing system we verify its validity and show its future effect.
Design and Implementation of Embedded Linux Router
Ju, Min-Gyu ; Choe, Gyeong-Hui ; Kim, Jong-Su ; Mun, Jong-Uk ; Jeong, Gi-Hyeon ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 339~344
In this paper, we describe the issues associated with implementing embedded Linux system. As an example of embedded system, a router which utilizes the powerful networking capability of Linux is implemented and the details of porting Linux to the dedicated hardware is discussed. Several efficient methods to avoid performance degradation resulted from porting lap top computer oriented Linux to embedded system are suggested. To verify the eligibility of the method to embed Linux into standalone system and to see the performance of the implemented router, comparison data with one of the most popular routers is presented.
A Design and Implementation of the Real-Time VoIP Terminal System Based on Linux
Lee, Myeong-Geun ; Lee, Sang-Jeong ; Seo, Jeong-Min ; Im, Jae-Yong ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 345~352
In this paper, a VoIP (Voice on Internet Protocol) terminal system, which can process voice in real time based on Linux, is designed and implemented. The hardware of it is designed using a i486 processor and a DSP codec chip which encodes and decodes voice data in real time. As an operating system, RTLinux, which is a real-time operating system based on Linux, is ported to manage real-time voice processing. The voice processing module of the system uses G.723.1 voice codec of ITU-T standard. It transfers voice data within 30ms to assure good voice quality. In order to satisfy the real time requirements and QoS (Quality-of-Service) for the voice data, the real-time voice processing device driver is designed and implemented. To verify the system, the chatting application program is developed and tested for QoS of the system
The Implementation and Performance Testing of Real Time Information Processing System
Jeong, Yoon-Seok ; Kim, In-Su ; Kim, Tae-Wan ; Kim, Kee-Cheon ; Chang, Chun-Hyon ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 353~358
In recent days, pc can process many things that mainframe have processed. Especially, in the transition from mainframe to pc, industries have needed the capabilities of Real Time information processing and Real Time monitoring for information control. But to support Real Time properties, it's needed to add Real Time modules and verify them. In this dissertation, we implemented and verified the Real Time System to support Real Time property. In addition, we implemented Web-based Real Time Monitoring System for Real Time information monitoring.
Failure Recovery in the Linux Cluster File System SANiqueTM
Lee, Gyu-Ung ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 359~366
This paper overviews the design of SANique
-a shred file system for Linux cluster based on SAN environment. SANique
has the capability of transferring user data from network-attached SAN disks to client applcations directly without the control of centralized file server system. The paper also presents the characteristics of each SANique
subsystem: CFM(Cluster File Manager), CVM(Cluster Volume Manager), CLM(Cluster Lock Manager), CBM(Cluster Buffer Manager) and CRM(Cluster Recovery Manager). Under the SANique
design layout, then, the syndrome of '||'&'||'quot;split-brain'||'&'||'quot; in shared file system environments is described and defined. The work first generalizes and illustrates possible situations in each of which a shared file system environment may split into two or more pieces of separate brain. Finally, the work describes the SANique
approach to the given "split-brain"problem using SAN disk named "split-brain" and develops the overall recovery procedure of shared file systems.
Metadata Management of a SAN-Based Linux Cluster File System
Kim, Shin-Woo ; Park, Sung-Eun ; Lee, Yong-Kyu ; Kim, Gyoung-Bae ; Shin, Bum-Joo ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 367~374
Recently, LINUX cluster file systems based on the storage area network (SAN) have been developed. In those systems, without using a central file server, multiple clients sharing the whole disk storage through Fibre Channel can freely access disk storage and act as file servers. Accordingly, they can offer advantages such as availability, load balancing, and scalability. In this paper, we describe metadata management schemes designed for a new SAN-based LINUX cluster file system. First, we present a new inode structure which is better than previous ones in disk block access time. Second, a new directory structure which uses extendible hashing is described. Third, we describe a novel scheme to manage free disk blocks, which is suitable for very large file systems. Finally, we present how we handle metadata journaling. Through performance evaluation, we show that our proposed schemes have better performance than previous ones.
An Efficient Recovery Technique using Global Buffer on SAN Environments
Park, Chun-Seo ; Kim, Gyeong-Bae ; Lee, Yong-Ju ; Park, Seon-Yeong ; Sin, Beom-Ju ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 375~384
The shared disk file systems use a technique known as file system journaling to support recovery of metadata on the SAN(Storage Area Network). In the existing journaling technique, the metadata that is dirtied by one host must be updated to disk space before some hosts access it. The system performance is decreased because the disk access number is increased. In this paper, we describe a new recovery technique using a global buffer to decrease disk I/O. It transmits the dirtied metadata into the other hosts through Fibre Channel network on the SAN instead of disk I/O and supports recovery of a critical data by journaling a data as well as metadata.
The Blocking of buffer overflow based attack for Linux kernel
Kim, Jeong-Nyeo ; Jeong, Gyo-Il ; Lee, Cheol-Hun ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 385~390
In this paper, we describe a blocking method of buffer overflow attack for secure operating system. Our team developed secure operating system using MAC and ACL access control added on Linux kernel. We describe secure operating system (SecuROS) and standardized Secure utility and library. A working prototype able to detect and block buffer overflow attack is available.
E-BLP Security Model for Secure Linux System and Its Implementation
Gang, Jeong-Min ; Sin, Uk ; Park, Chun-Gu ; Lee, Dong-Ik ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 391~398
To design and develop secure operating systems, the BLP (Bell-La Padula) model that represents the MLP (Multi-Level Policy) has been widely adopted. However, user\`s security level in the most developed systems based on the BLP model is inherited to a process that is actual subject on behalf of the user, regardless whatever the process behavior is. So, there could be information disclosure threat or modification threat by malicious or unreliable processes even though the user is authorized in the system. These problems can be solved by defining the subject as (user, process) ordered pair and by defining the process reliability. Moreover, when the leveled programs which exist as objects in a disk are executed by a process and have different level from the process level, the security level decision problem occurs. This paper presents an extended BLP (E-BLP) model in which process reliability is considered and solves the security level decision problem. And this model is implemented into the Linux kernel 2.4.7.
evelopment of Java Class Library For E-Book Reader Systems on Embedded Linux Environment
Lee, Eun-Jeong ; Jo, Su-Seon ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 399~410
We developed a Java library Xeni for e-book reader systems on embedded Linux environment. Xeni is an API library providing functions such as rendering for XML-based e-book contents, navigation mechanism for readers and bookmark management. This library is developed in Java language, targeting java virtual machines on embedded Linux systems. We discuss design and structure of the developed library, and introduce the reference implementation of a reader system using this library. Also, virtual machines on Linux environment are briefly surveyed.
The Design and Implementation of a Home Network Management System through a Web Browser
O, Bong-Jin ; Kim, Chae-Gyu ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 411~418
This paper describes the design and implementation of a home network management system through a web browser. All digital devices are connected to a set-top box on which personal java environment is installed through an IEEE1394 serial bus. The embedded web server on the set-top box supports persistent-connection of HTTP1.1 and servlet engine for JSDK2.1. The home network management system is developed as the form of a servlet and uses JNI to access IEEE1394 device driver\`s APIs. When a client selects an icon related with a device the user interface applet of the device is downloaded into a client\`s web browser and communicates with a related servlet through TCP/IP APIs.
A Dual Slotted Ring Organization for Reducing Memory Access Latency in Distributed Shared Memory System
Min, Jun-Sik ; Chang, Tae-Mu ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 419~428
Advances in circuit and integration technology are continuously boosting the speed of processors. One of the main challenges presented by such developments is the effective use of powerful processors in shared memory multiprocessor system. We believe that the interconnection problem is not solved even for small scale shared memory multiprocessor, since the speed of shared buses is unlikely to keep up with the bandwidth requirements of new powerful processors. In the past few years, point-to-point unidirectional connection have emerged as a very promising interconnection technology. The single slotted ring is the simplest form point-to-point interconnection. The main limitation of the single slotted ring architecture is that latency of access increase linearly with the number of the processors in the ring. Because of this, we proposed the dual slotted ring as an alternative to single slotted ring for cache-based multiprocessor system. In this paper, we analyze the proposed dual slotted ring architecture using new snooping protocol and enforce simulation to compare it with single slotted ring.
Design and Implementation of Real-Time Operating System for a GPS Navigation Computer
Bae, Jang-Sik ; Song, Dae-Gi ; Lee, Cheol-Hun ; Song, Ho-Jun ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 429~438
GPS (Global Positioning System) is the most ideal navigation system which can be used on the earth irrespective of time and weather conditions. GPS has been used for various applications such as construction, survey, environment, communication, intelligent vehicles and airplanes and the needs of GPS are increasing in these days. This paper deals with the design and implementation of the RTOS (Real-Time Operating System) for a GPS navigation computer in the GPS/INS integrated navigation system. The RTOS provides the optimal environment for execution and the base platform to develop GPS application programs. The key facilities supplied by the RTOS developed in this paper are priority-based preemptive scheduling policy, dynamic memory management, intelligent interrupt handling, timers and IPC, etc. We also verify the correct operations of all application tasks of the GPS navigation computer on the RTOS and evaluate the performance by measuring the overhead of using the RTOS services.
Improving Performance of Large Sparse Linear System Solvers On Distributed Memory Systems By Asynchronous Algorithms
Park, Pil-Seong ; Sin, Sun-Cheol ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 439~446
The main stream of parallel programming today is using synchronous algorithms, where processor synchronization for correct computation and workload balance are essential. Overall performance of the whole system is dependent upon the performance of the slowest processor, if workload is not well-balanced or heterogeneous clusters are used. Asynchronous iteration is a way to mitigate such problems, but most of the works done so far are for shared memory systems. In this paper, we suggest and implement a parallel large sparse linear system solver that improves performance on distributed memory systems like clusters by reducing processor idle times as much as possible by asynchronous iterations.
Prefetching Policy based on File Acess Pattern and Cache Area
Lim, Jae-Deok ; Hwang-Bo, Jun-Hyeong ; Koh, Kwang-Sik ; Seo, Dae-Hwa ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 447~454
Various caching and prefetching algorithms have been investigated to identify and effective method for improving the performance of I/O devices. A prefetching algorithm decreases the processing time of a system by reducing the number of disk accesses when an I/O is needed. This paper proposes an AMBA prefetching method that is an extended version of the OBA prefetching method. The AMBA prefetching method will prefetching blocks continuously as long as disk bandwidth is enough. In this method, though there were excessive data request rate, we would expect efficient prefetching. And in the AMBA prefetching method, to prevent the cache pollution, it limits the number of data blocks to be prefetched within the cache area. It can be implemented in a user-level File System based on a Linux Operating System. In particular, the proposed prefetching policy improves the system performance by about 30∼40% for large files that are accessed sequentially.
An Efficient Dynamic Load balancing Strategy for Tree-structured Computations
Hwang, In-Jae ; Hong, Dong-Kweon ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 455~460
For some applications, the computational structure changes dynamically during the program execution. When this happens, static partitioning and allocation of tasks are not enough to achieve high performance in parallel computers. In this paper, we propose a dynamic load balancing algorithm efficiently distributes the computation with dynamically growing tree structure to processors. We present an implementation technique for the algorithm on mesh architectures, and analyze its complexity. We also demonstrate through experiments how our algorithm provides good quality solutions.
Implementation and Performance Analysis of Group Communication using the CORBA & JAVA
Choe, Man-Eok ; Gu, Yong-Wan ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 461~468
Large-scale distributed applications based on Internet and client/server applications have to deal with series of problems such as load balancing, unpredictable communication delays, partial errors, and networking failures. Therefore, sophisticated applications such as teleconferencing, video-on-demand, and concurrent software engineering require an abstracted communication. In this paper, we present our design, implementation and performance analysis of group communication using the CORBA ORB, JAVA RMI, Socket based on distributed computing. We anticipate our study may apply to the various field of applications such as fault-tolerant client/server system, groupware, scalable text retrieval system, and financial information systems.
A Page Replacement Scheme Based on Recency and Frequency
Lee, Seung-Hoon ; Lee, Jong-Woo ; Cho, Seong-Je ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 469~478
In the virtual memory system, page replacement policy exerts a great influence on the performance of demand paging. There are LRU(Least Recently Used) and LFU (Least Frequently Used) as the typical replacement policies. The LRU policy performs effectively in many cases and adapts well to the changing workloads compared to other policies. It however cannot distinguish well between frequently and infrequently referenced pages. The LFU policy requires that the page with the smallest reference count be replaced. Though it considers all the references in the past, it cannot discriminate between references that occurred far back in the past and the more recent ones. Thus, it cannot adapt well to the changing workload. In this paper, we first analyze memory reference patterns of eight applications. The patterns show that the recently referenced pages or the frequently referenced pages are accessed continuously as the case may be. So it is rather hard to optimize page replacement scheme by using just one of the LRU or LFU policy. This paper makes an attempt to combine the advantages of the two policies and proposes a new page replacement policy. In the proposed policy, paging list is divided into two lists (LRU and LFU lists). By keeping the two lists in recency and reference frequency order respectively, we try to restrain the highly referenced pages in the past from being replaced by the LRU policy. Results from trace-driven simulations show that there exists points on the spectrum at which the proposed policy performs better than the previously known policies for the workloads we considered. Especially, we can see that our policy outperforms the existing ones in such applications that have reference patterns of re-accessing the frequently referenced pages in the past after some time.
Topology of High Speed System Emulator and Its Software
Kim, Nam-Do ; Yang, Se-Yang ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 479~488
As the SoC designs complexity constantly increases, the simulation that uses their software models simply takes too much time. To solve this problem, FPGA-based logic emulators have been developed and commonly used in the industry. However, FPGA-based logic emulators are facing with the problems of which not only very low FPGA resource usage rate due to the very limited number of pins in FPGAs, but also the emulation speed getting slow drastically as the complexity of designs increases. In this paper, we proposed a new innovative emulation architecture and its software that has high FPGA resource usage rate and makes the emulation extremely fast. The proposed emulation system has merits to overcome the FPGA pin limitation by pipelined ring which transfers multiple logic signal through a single physical pin, and it also makes possible to use a high speed system clock through the intelligent ring topology. In this topology, not only all signal transfer channels among EPGAs are totally separated from user logic so that a high speed system clock can be used, but also the depth of combinational paths is kept swallow as much as possible. Both of these are contributed to achieve high speed emulation. For pipelined singnals transfer among FPGAs we adopt a few heuristic scheduling having low computation complexity. Experimental result with a 12 bit microcontroller has shown that high speed emulation possible even with these simple heuristic scheduling algorithms.
A Localized Multiquadric (MQ) Interpolation Method on the Hyperbolic Plane
Park, Hwa-Jin ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 489~498
A new method for local control of arbitrary scattered data interpolation in the hyperbolic plane is developed in this paper. The issue associated with local control is very critical in the interactive in the interactive design field. Especially the suggested method in this paper could be effectively applied to the interactive shape modeling of genus-N objects, which are constructed on the hyperbolic plane. Since the effects of the changed data affects only the limited area around itself, it is more convenient for end-users to design a genus-N object interactively. Therefore, by improving the global interpolation on the hyperbolic plane where the genus-N object is constructed, this research is aiming at the development and implementation of the local interpolation on the hyperbolic plane. It is implemented using the following process. First, for localizing the interpolating functions, the hyperbolic domain is tessellated into arbitrary triangle patches and the group of adjacent triangle patches of each data point is defined as a sub-domain. On each sub-domain, a weight function is defined. Last, by blending of three weight functions on the overlapped triangles, local MQ interpolation is completed. Consequently, it is compared with the global MQ interpolation using several sample data and functions.
A Fast Fractal Image Compression Using The Normalized Variance
Kim, Jong-Koo ; Hamn, Do-Yong ; Wee, Young-Cheul ; Kimn, Ha-Jine ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 499~502
Fractal image coding suffers from the long search time of domain pool although it provides many properties including the high compression ratio. We find that the normalized variance of a block is independent of contrast, brightness. Using this observation, we introduce a self similar block searching method employing the d-dimensional nearest neighbor searching. This method takes Ο(log/N) time for searching the self similar domain blocks for each range block where N is the number of domain blocks. PSNR (Peak Signal Noise Ratio) of this method is similar to that of the full search method that requires Ο(N) time for each range block. Moreover, the image quality of this method is independent of the number of edges in the image.
A Study on Improvement of Wegmann's method by Low Frequency pass Filter
Song, Eun-Jee ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 503~508
Conformal mapping is useful to solve problems in heat conduction, electrostatic potential and fluid flow involving Laplace's equation in two independent variables. Determinations of conformal maps from the unit disk onto a Jordan region eventually requires solving the Theodorsen equation which is in general nonlinear with respect to the boundary correspondence function. H bner's method which has been well known for the efficient method among the many suggestions for the Theodorsen equation, was improved in early study[1, 2]. In this paper Wegmann's method is treated that is more efficient in computation cost rather than H bner's. But we found that a question which is divergent in some difficult problems by numerical experiment of Wegmann's iteration. We analyze theoretically the cause of divergence and propose an improved method by applying a low frequency filter to the Wegmann's method. Numerical experiments by our improved method show convergence for all divergent problems by Wegmann's method.
An Analysis System for Whole Genomic Sequence Using String B-Tree
Choe, Jeong-Hyeon ; Jo, Hwan-Gyu ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 509~516
As results of many genome projects, genomic sequences of many organisms are revealed. Various methods such as global alignment, local alignment are used to analyze the sequences of the organisms, and k -mer analysis is one of the methods for analyzing the genomic sequences. The k -mer analysis explores the frequencies of all k-mers or the symmetry of them where the k -mer is the sequenced base with the length of k. However, existing on-memory algorithms are not applicable to the k -mer analysis because a whole genomic sequence is usually a large text. Therefore, efficient data structures and algorithms are needed. String B-tree is a good data structure that supports external memory and fits into pattern matching. In this paper, we improve the string B-tree in order to efficiently apply the data structure to k -mer analysis, and the results of k -mer analysis for C. elegans and other 30 genomic sequences are shown. We present a visualization system which enables users to investigate the distribution and symmetry of the frequencies of all k -mers using CGR (Chaotic Game Representation). We also describe the method to find the signature which is the part of the sequence that is similar to the whole genomic sequence.
Design of Multi-agent System for Course Scheduling of Learner-oriented using Weakness Analysis Algorithm
Kim, Tae-Seog ; Lee, Jong-Hee ; Lee, Keun-Wang ; Oh, Hae-Seok ;
The KIPS Transactions:PartA, volume 8A, issue 4, 2001, Pages 517~522
The appearance of web technology has accelerated a role of the development of the multimedia technology, the computer communication technology and the multimedia application contents. And serveral researches of WBI (Web-based Instruction) system have combined the technology of the digital library and LOD. Recently WBI (Web-based Instruction) model which is based on web has been proposed in the part of the new activity model of teaching-learning. And the demand of the customized coursewares which is required from the learners is increased, the needs of the efficient and automated education agents in the web-based instruction are recognized. But many education systems that had been studied recently did not service fluently the courses which learners had been wanting and could not provide the way for the learners to study the learning weakness which is observed in the continuous feedback of the course. In this paper we propose "Design of Multi-agent System for Course Scheduling of Learner-oriented using Weakness Analysis Algorithm". First proposed system monitors learner's behaviors constantly, evaluates them, and calculates his accomplishment. From this accomplishment the multi-agent schedules the suitable course for the learner. And the learner achieves a active and complete learning from the repeated and suitable course.le course.