Oh-Han Kang

Optical-LSP Establishment and a QoS Maintenance Scheme Based on Differentiated Optical QoS Classes in OVPNs

A “virtual private network (VPN) over Internet” has the benefit of being cost-effective and flexible. However, it has difficulties providing sufficient QoS and adequate transmission capacity for high bandwidth services. Given the increasing demand for high bandwidth Internet and the demand for QoS assurances in a “VPN over Internet”, IP/generalized multi-protocol label switching (GMPLS) based on a control plane combined with a high-bandwidth, dense-wavelength division multiplexing (DWDM) optical network is seen as a very favorable approach for realizing the future “optical VPN (OVPN) over IP/GMPLS over DWDM”. Within this architecture, providing QoS guaranteed multimedia services with a differentiated QoS guaranteed protocol framework with QoS recovery is one of the key issues to implement. Therefore, we suggest in this paper optical-label switched path (O-LSP) establishment and its QoS maintenance scheme based on differentiated optical QoS-service (DOQoS) classes. They are the key components for this DOQoS framework in assuring end-to-end QoS in an “OVPN over IP/GMPLS over DWDM” architecture.

Control Mechanism for QoS Guaranteed Multicast Service in OVPN over IP/GMPLS over DWDM

OVPN over IP/GMPLS over DWDM technology with QoS assurances is considered as a promising approach for the next generation OVPN. In this paper, we suggest a multicast OLSP (Optical Label Switched Path) establishment mechanism for supporting high bandwidth multicast services in OVPN over IP/GMPLS over DWDM. For the establishment of the multicast OLSP, we propose a new multicast tree generation algorithm VS-MIMR that finds the minimum interference path between virtual source nodes. We also suggest an entire OVPN control mechanism to adapt the operation of the routing and signaling protocols of GMPLS.

S3MP: a task duplication based scalable scheduling algorithm for symmetric multiprocessors

We present a task duplication based scalable scheduling algorithm for Symmetric Multiprocessors (SMP), called S3MP (Scalable Scheduling for SMP), to address the problem of task scheduling. The algorithm pre-allocates network communication resources so as to avoid potential communication conflicts, and generates a schedule for the number of processors available in an SMP. This algorithm employs heuristics to select duplication of tasks so that schedule length is reduced/minimized. The performance of the S3MP algorithm has been observed by comparing the schedule length under various number of processors and the ratio of communication to computation cost. This algorithm also has been applied to some practical directed acyclic graphs (DAGs).

Virtual source-based minimum interference path multicast routing in optical virtual private networks

Virtual Private Network (VPN) services over the Internet are gaining increased acceptance due to the economic benefits and flexibility. However, with difficulties of providing sufficient transmission capacity for value-added and mission-critical services, the Optical VPN (OVPN) deploying Dense Wavelength-Division Multiplexing (DWDM) technology has been seen as a favorable approach for realizing the future VPN services. In an OVPN, the Routing and Wavelength Assignment problem plays a key role for capacity utilization and therefore the Multicast Routing and Wavelength Assignment problem has been the dominant issue in a DWDM-based OVPN. In this paper, using Virtual Source (VS) nodes that have splitting and wavelength conversion capabilities, we propose a new Multicast Routing and Wavelength Assignment method for multicast sessions. The algorithm combines the VS-based tree generation approach with Multi-Wavelength Minimum Interference Path Routing (MW-MIPR) that chooses a path that does not interfere too much with potential future multicast session requests.

A Web-based Toolkit for Scheduling Simulation Using GridSim

We implemented a Web-based grid scheduling platform, which can model a system and simulate a scheduling method in grid computing. The scheduling platform is able to perform resource modeling, task modeling, algorithm compiling, simulation, and performance evaluation rapidly in a Web environment. The implemented scheduling platform can be applied as a foundation for grid research and can be used to analyze the efficiency of the scheduling algorithm

Scalable scheduling for symmetric multiprocessors (SMP)

We present a task duplication-based scalable scheduling algorithm for Symmetric Multiprocessors (SMP), called S3MP (Scalable Scheduling for SMP), to address the problem of task scheduling. The algorithm pre-allocates network communication resources so as to avoid potential communication conflicts, and generates a schedule for the number of processors available in a SMP. This algorithm employs heuristics to select duplication of tasks so that schedule length is reduced/minimized. The algorithm can schedule the tasks of a directed acyclic graph (DAG) on to the processors of SMP with a worst case time complexity O(V2), where V is the number nodes of the DAG. The performance of the S3MP algorithm has been observed by comparing the schedule length under various number of processors and the ratio of communication to computation cost. This algorithm also has been applied to some practical DAGs.

A task duplication based scheduling algorithm for shared memory multiprocessors

We present a task duplication based scheduling algorithm for shared memory multiprocessors (SMPs), called S2MP (scheduling for SMP), to address the problem of task scheduling. This algorithm employs heuristics to select duplication of tasks so that schedule length is reduced/minimized. The performance of the S2MP algorithm has been observed by comparing the schedule length under various number of processors and the ratio of communication to computation cost.

The Analysis of ‘General Computer’ Textbooks in Commerce․Information High Schools

In this paper, both content analysis and Romey analysis were employed to analyze three `General Computer` textbooks used in commerce and information high schools. The content analysis was employed to study the organization and contents of the textbooks, whereas the Romey analysis to determine the inquisitive tendency of four sections - Text, Data, Activity and Evaluation. The results from the content analysis showed that textbooks differed in the number of subsections, the number of pages in each section, and the number of concepts introduced in each section. Also, results from the Romey analysis demonstrated that the section Text in all the textbooks was written with a low level of inquisitive tendency, but also that they differed in that two other sections Data and Activity in one textbook exhibited a high level of inquisitive tendency while the other section Evaluation in two textbooks did. Using the aforementioned results, we proposed ways to improve the readability of `General Computer` textbooks.

Multicast OLSP establishment scheme in OVPN over IP/GMPLS over DWDM

OVPN (Optical Virtual Private Network) over IP (Internet Protocol)/GMPLS (Generalized Multi-Protocol Label Switching) over DWDM (Dense Wavelength Division Multiplexing) technology with QoS assurances is considered as a promising approach for the next generation OVPN. In this paper, we suggest a multicast OLSP (Optical Label Switched Path) establishment mechanism for supporting high bandwidth multicast services. For the establishment of the multicast OLSP, we propose a new multicast tree generation algorithm VS-MIMR (Virtual Source-based Minimum Interference Multicast Routing) that finds the minimum interference path between virtual source nodes. We also suggest an entire OVPN control mechanism to adapt the operation of the routing and signaling protocols of GMPLS.

Analysis of Inquisitive Tendency of 2009 Revised Middle School Informatics Textbooks

In this paper, we study the inquisitive tendency in informatics textbooks for middle school students. These textbooks were written in 2009, and have been adopted in 2013 as part of the curriculum. The research is based on six textbooks, which passed qualification tests, and is mainly focused on the section `composition and movement of information equipment`, which covers contents for the student`s major field of study. Romey analysis was employed to analyze inquisitive tendency in four sections - text, data, activity and evaluation. The results illustrated that some textbooks were organized in a way that exhibited a low level of inquisitive tendency for students, and took an authoritative tone. The section `activity` showed the highest level of inquisitive tendency and the `text` showed the lowest level. Some sections in the textbooks were found to have zero Romey measures, which stress the need for improvement.