• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.546-552
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• 2000

The decoding of Turbo-Code relies on the application of a soft input/soft output decoders which can be realized using maximum-a-posteriori(MAP) symbol estimator[l]. Radix-2 MAP decoder can not be used for high speed communications because of a large number of interleaver block size N. This paper proposed a new simple method for radix-4 MAP decoder based on radix-2 MAP decoder in order to reduce the interleave block size. A branch metrics, forward and backward recursive functions are proposed for applying to radix-4 MAP structure with symbol interleaver. Radix-4 MAP decoder shall be illustratively described and its error performance capability shall be compared to conventional radix-2 MAP decoder in AWGN channel.

• Journal of Computing Science and Engineering
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• v.7 no.3
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• pp.168-176
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• 2013

Long-term evolution (LTE) is emerging as a major candidate for 4G cellular networks to satisfy the increasing demands for mobile broadband services, particularly multimedia delivery. Multiple-input multiple-output (MIMO) technology combined with orthogonal frequency division multiple access and more efficient modulation/coding schemes (MCS) are key physical layer technologies in LTE networks. However, in order to fully utilize the benefits of the advances in physical layer technologies, the MIMO configuration and MCS need to be dynamically adjusted to derive the promised gains of 4G at the application level. This paper provides a performance evaluation of video traffic with variations in the physical layer transmission parameters to suit the varying channel conditions. A quantitative analysis is provided using the perceived video quality as a video quality measure (evaluated using no-reference blocking and blurring metrics), as well as transmission delay. Experiments are performed to measure the performance with changes in modulation and code rates in poor and good channel conditions. We discuss how an adaptive scheme can optimize the performance over a varying channel.

• International Journal of Contents
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• v.5 no.2
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• pp.6-15
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• 2009

Recently many different programming languages have emerged for the development of bioinformatics applications. In addition to the traditional languages, languages from open source projects such as BioPerl, BioPython, and BioJava have become popular because they provide special tools for biological data processing and are easy to use. However, it is not well-studied which of these programming languages will be most suitable for a given bioinformatics task and which factors should be considered in choosing a language for a project. Like many other application projects, bioinformatics projects also require various types of tasks. Accordingly, it will be a challenge to characterize all the aspects of a project in order to choose a language. However, most projects require some common and primitive tasks such as file I/O, text processing, and basic computation for counting, translation, statistics, etc. This paper presents the benchmarking results of six popular languages, Perl, BioPerl, Python, BioPython, Java, and BioJava, for several common and simple bioinformatics tasks. The experimental results of each language are compared through quantitative evaluation metrics such as execution time, memory usage, and size of the source code. Other qualitative factors, including writeability, readability, portability, scalability, and maintainability, that affect the success of a project are also discussed. The results of this research can be useful for developers in choosing an appropriate language for the development of bioinformatics applications.

• Journal of Communications and Networks
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• v.17 no.6
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• pp.582-591
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• 2015

A massive distributed storage system is the foundation for big data operations. Access latency performance is a key metric in distributed storage systems since it greatly impacts user experience while existing codes mainly focus on improving performance such as storage overhead and repair cost. By generating parity nodes from parity nodes, in this paper we design new XOR-based erasure codes hierarchical tree structure code (HTSC) and high failure tolerant HTSC (FH HTSC) to reduce access latency in distributed storage systems. By comparing with other popular and representative codes, we show that, under the same repair cost, HTSC and FH HTSC codes can reduce access latency while maintaining favorable performance in other metrics. In particular, under the same repair cost, FH HTSC can achieve lower access latency, higher or equal failure tolerance and lower computation cost compared with the representative codes while enjoying similar storage overhead. Accordingly, FH HTSC is a superior choice for applications requiring low access latency and outstanding failure tolerance capability at the same time.

• Journal of the Korea Society for Simulation
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• v.22 no.1
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• pp.41-51
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• 2013

This tutorial paper presents the design methodology of system-level simulators targeted for code division multiple access (CDMA) cellular standards such as EV-DO (Evolution-Data Only) and broadcast multicast service (BCMCS). The basic structure and simulation flow of system-level simulators are delineated, following the procedure of cell layout, mobile drops, channel modeling, received power calculation, scheduling, packet error prediction, and traffic generation. Packet data transmissions on the forward link of CDMA systems and EV-DO BCMCS systems are considered for modeling simulators. System-level simulators for cellular standards are modeled and developed with high-level languages and utilized to evaluate and predict air interface performance metrics including capacity and coverage.

• KIISE Transactions on Computing Practices
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• v.22 no.8
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• pp.351-356
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• 2016

In recent years, as smartphones with Android platforms expand, the number of Android applications increases. Android applications implement Java and XML to compose the user interface, among other things. Between Java and XML, various problems may occur. Nonetheless, static analysis research and tools are not sufficient. In this paper we will list the problems which may occur between Java and XML. Subsequently, we will propose a detection method for them. Using the proposed technique, we found 172 Android-specific problems and 35 performance drop issues in 150 Android applications in the Google Play Store. We would like to contribute to research into static analysis and software quality improvement.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.2
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• pp.105-114
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• 2000

In this paper, we propose a bandwidth-efficient channel coding scheme using the turbo trellis-coded modulation with multiple symbol detection. The turbo code can achieve good bit error rates (BER) at low SNR. That comprises two binary component codes and an interleaver. TCM codes combine modulation and coding by optimizing the euclidean distance between codewords. This can be decoded with the Viterbi or the symbol-by- symbol MAP algorithm. But we present the MAP algorithm with branch metrics of the Euclidean distance of the first phase difference as well as the Lth phase difference. The study shows that the turbo trellis-coded modulation with multiple symbol detection can improve the BER performance at the same SNR.

• International Journal of Computer Science & Network Security
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• v.23 no.6
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• pp.107-114
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• 2023

Successful implementations of DevOps practices significantly improvise software efficiency, collaboration and security. Most of the organizations are adopting DevOps for faster and quality software delivery. DevOps brings development and operation teams together to overcome all kind of communication gaps responsible for software failures. It relies on different sets of alternative tools to automate the tasks of continuous integration, testing, delivery, deployment and monitoring. Although DevOps is followed for being very reliable and responsible environment for quality software delivery yet it lacks many quantifiable aspects to prove it on the top of other traditional and agile development methods. This research evaluates quantitative performance of DevOps and traditional/ agile development methods based on software metrics. This research includes three sample projects or code repositories to quantify the results and for DevOps integrated selective tool chain; current research considers our earlier proposed and implemented DevOps hybrid model of integrated automation tools. For result discussion and validation, tabular and graphical comparisons have also been included to retrieve best performer model. This comparative and evaluative research will be of much advantage to our young researchers/ students to get well versed with automotive environment of DevOps, latest emerging buzzword of development industries.

• The Journal of Korea Robotics Society
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• v.7 no.4
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• pp.292-298
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• 2012

It is a real-time system that the system correctness depends not only on the correctness of the logical result of the computation but also on the result delivery time. Real-time Operating System (RTOS) is a software that manages the time of a microprocessor to ensure that the most important code runs first so that it is a good building block to design the real-time system. The real-time performance is achieved by using real-time mechanisms through data communication and synchronization of inter-task communication (ITC) between tasks. Therefore, test on the response time of real-time mechanisms is a good measure to predict the performance of real-time systems. This paper aims to analysis the response characteristics of real-time mechanisms in kernel space for real-time embedded Linux: RTAI and Xenomai. The performance evaluations of real-time mechanism depending on the changes of task periods are conducted. Test metrics are jitter of periodic tasks and response time of real-time mechanisms including semaphore, real-time FIFO, Mailbox and Message queue. The periodicity of tasks is relatively consistent for Xenomai but RTAI reveals smaller jitter as an average result. As for real-time mechanisms, semaphore and message transfer mechanism of Xenomai has a superior response to estimate deterministic real-time task execution. But real-time FIFO in RTAI shows faster response. The results are promising to estimate deterministic real-time task execution in implementing real-time systems using real-time embedded Linux.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.768-777
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• 2020

In this paper, we describe recent research results on AODV routing protocol, which is widely deployed at mobile ad hoc networks, and AODV related routing protocols with multi-path routing schemes. We suggest the critical problems which minimum hop routing schemes have, such as AODV routing protocol, and then, propose a new C-AODV routing protocol with two routing metrics: the primary metric is the hop count, the secondary metric is the sum of link delay times. We implemented C-AODV protocol by modifying AODV at the NS-3, and thus, elaborate on how we change the original AODV source code of NS-3 in order to implement the C-AODV scheme. We show numerical comparison of C-AODV scheme with the original AODV scheme and then, discuss how much the C-AODV enhances routing performance over AODV protocol. In conclusion, we present future research items.