• Management Science and Financial Engineering
• /
• v.6 no.2
• /
• pp.29-45
• /
• 2000

We consider the design of a two-level telecommunication network having logical full-mesh/star topology, with the implementation of conduit systems taken together. The design problem is then viewed as consisting of three subproblems: locating hub facilities, placing a conduit network, and installing cables therein to configure the logical full-mesh/star network. Without partitioning into subproblems as done in the conventional approach, the whole problem is directly dealt with in a single integrated framework, inspired by some recent successes with the approach. We successfully formulate the problem as a variant of the classical multicommodity flow model for the fixed charge network design problem, aided by network augmentation, judicious commodity definition, and some flow restrictions. With our optimal model, we solve some randomly generated sample problems by using CPLEX MIP program. From the computational experiments, it seems that our model can be applied to the practical problem effectively.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.3
• /
• pp.647-660
• /
• 1995

Given the tetrahedron-based octree approximation of a solid as described in part(I) of this thesis, in this part(II) a systematic procedure of 'boundary moving' is developed for the fully automatic generation of 3D finite element meshes. The algorithm moves some vertices of the octants near the boundary onto the exact surface of a solid without transforming the topology of octree leaf elements. As a result, the inner octree leaf elements can be used as exact tetrahedral finite element meshes. In addition, as a quality measure of a tetrahedral element, 'shape value' is propopsed and used for the generation of better finite elements during the boundary moving process.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.2 no.2
• /
• pp.116-122
• /
• 2007

System management application system is one of the most interesting fields in Ubiquitous Sensor Networks. It conforms to the property of Ubiquitous Sensor Networks very well, and it is the closest application for commercial use. We have two kinds of system management technology, such as the one which is accessed by web browser at anytime, anywhere and another one which is for local accessed system. In this paper, our purpose is implementation of system management application system which provides Mesh Sensor Networks topology with IP based agent platform and system management server. Furthermore we introduce the functions used for our recent implementation and propose several future issues about system management application system.

• Journal of Information Processing Systems
• /
• v.10 no.2
• /
• pp.193-214
• /
• 2014

Load balancing is the major benefit of any distributed system. To facilitate this advantage, task duplication and migration methodologies are employed. As this paper deals with dependent tasks (DAG), we used duplication. Task duplication reduces the overall schedule length of DAG along-with load balancing. This paper proposes a new task duplication algorithm at the time of tasks assignment on various processors. With the intention of conducting proposed algorithm performance computation; simulation has been done on the Netbeans IDE. The mesh topology of a distributed system is simulated at this juncture. For task duplication, overall schedule length of DAG is the main parameter that decides the performance of a proposed duplication algorithm. After obtaining the results we compared our performance with arbitrary task assignment, CAWF and HEFT-TD algorithms. Additionally, we also compared the complexity of the proposed algorithm with the Duplication Based Bottom Up scheduling (DBUS) and Heterogeneous Earliest Finish Time with Task Duplication (HEFT-TD).

• Annual Conference of KIPS
• /
• 2012.11a
• /
• pp.799-801
• /
• 2012

Wireless Mesh Network (WMN) can be defined as a communication network consisting of radio nodes organized in a mesh topology, which has been attracting much attention due to its promising technology. This paper addressed the factors on how to design routing protocols for WMN. 2 examples of designing routing metric and routing algorithm are given for case study. With consideration of those factors such as wireless broadcast advantage (WBA)/channel assignment (CA) or intra-flow/inter-flow interference high throughput is achieved.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.5
• /
• pp.9-17
• /
• 2010

In this paper we propose an improved hierarchical routing protocol for wireless hybrid mesh network. The proposed method efficiently manages network topology and reduces overhead traffic for setting routing path by considering link stability. The simulation results show that the proposed method outperforms the HOLSR (hierarchical optimized link state routing) method in aggregate goodput, packet delivery ratio, and end-to-end delay.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.1
• /
• pp.183-200
• /
• 2020

This paper presents an efficient interactive framework for perspective scene completion and editing tasks, which are available largely in the real world but rarely studied in the field of image completion. Considering that it is quite hard to extract perspective information from a single image, this work starts from a friendly and portable interactive platform to obtain the basic perspective data. Then, in order to make this interface less sensitive, easier and more flexible, a perspective-rectification based correction mechanism is proposed to iteratively update the locations of the initial points selected by users. At last, a complanate mesh is generated by the geometry calculations from these corrected initial positions. This mesh must approximate the perspective direction and the structure topology as much as possible so that the filling process can be conducted under the constraint of the perspective effects of the original image. Our experiments show the results with good qualities and performances, and also demonstrate the validity of our approaches by various perspective scenes and images.

• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.1
• /
• pp.61-69
• /
• 1999

To promote the usability of CFD techniques for the basic hull form design, a hull surface mesh generating program, based on given station offsets and centerline profile, is developed. The new method employs non-uniform parametric splines with predetermined waterline end-shapes of natural spline, normal spline, ellipse, parabola hyperbola, and their combinations. Generated hull surface meshes can be utilized for potential panel method immediately and can be also used as a boundary grid surface for 3-D field grid system. Mesh topology chosen to represent hull surface can be transformed into a rectangle, which he1ps the flow solvers to transform surface meshes for the nonlinear free surface condition or to define the turbulence quantities. To prove the applicability, a container ship with bow and stem bulb is chosen, and the procedures generating hull surface meshes are described.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1283-1287
• /
• 2003

Reverse engineering technology refers to the process that creates a CAD model of an existing part using measuring devices. Recently, non-contact scanning devices have become more accurate and the speed of data acquisition has increased drastically. However, they generate thousands of points per second and various types of point data. Therefore. it becomes a important to handle the huge amount and various types of point data to generate a surface model efficiently. This paper proposes a new triangular mesh generation method using 3D grids. The geometric information of a part can be obtained from point cloud data by estimating normal values of the points. In our research, the non-uniform 3D grids are generated first for feature based data reduction based on the geometric information. Then, triangulation is performed with the reduced point data. The grid structure is efficiently used not only for neighbor point search that can speed up the mesh generation process but also for getting surface connectivity information to result in same topology surface with the point data. Through this integrated approach, it is possible to create surface models from scanned point data efficiently.

• Journal of Information Technology Applications and Management
• /
• v.15 no.1
• /
• pp.261-270
• /
• 2008

Wireless Mesh Networks (WMNs) have emerged as one of the new hot topics in wireless communications. WMNs have been suggested for use in situations in which some or all of the users are mobile or are located in inaccessible environments. Unconstrained transmission in a WMN may lead to the time overlap of two or more packet receptions, called collisions or interferences, resulting in damaged useless packets at the destination. There are two types of collisions; primary collision, due to the transmission of the stations which can hear each other, and hidden terminal collision, when stations outside the hearing range of each other transmit to the same receiving stations. For a WMN, direct collisions can be minimized by short propagation and carrier sense times. Thus, in this paper we only consider hidden terminal collision while neglecting direct collisions. To reduce or eliminate hidden terminal collision, code division multiple access (CDMA) protocols have been introduced. The collision-free property is guaranteed by the use of spread spectrum communication techniques and the proper assignment of orthogonal codes. Such codes share the fixed channel capacity allocated to the network in the design stage. Thus, it is very important to minimize the number of codes while achieving a proper transmission quality level in CDMA WMNs. In this paper, an efficient heuristic code assignment algorithm for eliminating hidden terminal collision in CDMA WMNs with general topology.