• Computational Structural Engineering
• /
• v.9 no.3
• /
• pp.209-216
• /
• 1996

The primary objective of this paper is to grasp many characteristics of buckling behavior of latticed spherical domes under various conditions. The Arc-Length Method proposed by E.Riks is used for the computation and evaluation of geometrically nonlinear fundamental equilibrium paths and bifurcation points. And the direction of the path after the bifurcation point is decided by means of Hosono's concept. Three different nonlinear stiffness matrices of the Slope-Deflection Method are derived for the system with rigid nodes and results of the numerical analysis are examined in regard to geometrical parameters such as slenderness ratio, half-open angle, boundary conditions, and various loading types. But in case of analytical model 2 (rigid node), the post-buckling path could not be surveyed because of Newton-Raphson iteration process being diversed on the critical point since many eigenvalues become zero simultaneously.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.3
• /
• pp.184-190
• /
• 2015

NVH engineering has become a hot issue due to radical technology changes and development in automotive industry since customers' expectations and needs for their vehicle is taken to a higher level. However, the source identification and quantification of the road noise within a vehicle is still not at the level where it needs to be to meet their expectations due to its' complex transfer path and difficulties in path optimization. The primary focus of this research is on direct force obtaining method at suspension hard points using suspension test rig. Directly obtained forces at suspension to body mounting points are critical and crucial for determining the effects of design changes of the suspension has on road noise performance. Direct force obtaining method has its limitation in sensor installation within an actual vehicle therefore, many has been indirectly calculating forces using full matrix inversion method or dynamic stiffness method. In this study, to circumvent this limitation, a suspension rig is used. Then, the suspension rig is verified through a comparative analysis of its dynamic behavior between the actual vehicle by cleat test on chassis dynamometer.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1997.03a
• /
• pp.140-143
• /
• 1997

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminium bar to investigate the basic flow characteristics. Considering the bonding mechanism of bi-metal contact surface as cold pressure welding, the normal pressure and the contact surface expansion are selected as process parameters governing the bonding condition. The critical pressure required for the bonding at the interface is obtained by solving a "local extrusion" using a slip line meyhod. A viscoplastic finite element method is used to analyze the steady state extrusion process. The boundary profile of bi-metal rod is predicted by tracking a particle path adjacent to interface surface. The variations of contact surface area and the normal pressure along the interface profile are predicted and compared to those by experiments.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2004.10a
• /
• pp.527-530
• /
• 2004

This paper presents an optimization formulation for resource scheduling in Critical Resource Diagramming (CRD) of production scheduling networks. A CRD network schedules units of resources against points of needs in a production network rather than the conventional approach of scheduling tasks against resource availability. This resource scheduling approach provides more effective tracking of utilization of production resources as they are assigned or 'moved' from one point of need to another. Using CRD, criticality indices can be developed for resource types in a way similar to the criticality of activities in Critical Path Method (CPM). In our supply chain model, upstreams may choose either normal operation or expedited operation in resource scheduling. Their decisions affect downstream's resource scheduling. The suggested optimization formulation models resources as CRD elements in a production two-stage supply to minimize the total operation cost

• KIEE International Transactions on Power Engineering
• /
• v.4A no.2
• /
• pp.58-68
• /
• 2004

This paper presents an optimal routing algorithm (ORA) for maximizing voltage stability as well as for minimizing power loss in radial power systems. In the proposed ORA, a novel voltage stability index (VSI) for real-time assessment is newly introduced based on the conventional critical transmission path framework. In addition, the suggested algorithm can automatically detect the critical transmission paths resulting in voltage collapse when additional real or reactive loads are added. To implement an effective ORA, we have developed an improved branch exchange (IBE) method based on a loss calculation index and tie-branch power flow equations, which are suggested for real-time applications. The proposed algorithm has been tested with IEEE test systems as well as a large-scale power system in Korea to demonstrate its effectiveness and efficiency.

• Structural Engineering and Mechanics
• /
• v.71 no.2
• /
• pp.139-151
• /
• 2019

In a project schedule, it is possible to reduce the time required to complete a project by allocating extra resources for critical activities. However, accelerating a project causes additional expense. This issue is addressed by finding optimal set of time-cost alternatives and is known as the time-cost trade-off problem in the literature. The aim of this study is to identify the optimal set of time-cost alternatives using a multiobjective teaching-learning-based optimization (TLBO) algorithm integrated with the non-dominated sorting concept and is applied to successfully optimize the projects ranging from a small to medium large projects. Numerical simulations indicate that the utilized model searches and identifies optimal / near optimal trade-offs between project time and cost in construction engineering and management. Therefore, it is concluded that the developed TLBO-based multiobjective approach offers satisfactorily solutions for time-cost trade-off optimization problems.

• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.201-208
• /
• 2011

Today's highly competitive construction scenario forces all the major players in the field to take up multiple projects which have put an undue pressure on the resources available within the organization. Under such a situation, there are many instances where in the resource requirement exceeds its availability due to multiple activities (with same resource requirement) which are scheduled to start simultaneously and thus results in the constrained resource becoming a bottleneck of the project. As a consequence of sharing resources, this paper studies the impact on the completion date of two similar projects under two different conditions, the first one resulting in a postponed end date and the second without any postponement. The resource utilization, the possibility of substitution of a resource and its subsequent impact on the deadline of the project is analyzed under these two circumstances. The study is done on a Critical Chain Project Management (CCPM) platform instead of leaving the schedule with a traditional Critical Path Method (CPM) finish, which gives an added advantage of validating the robustness of the emerging CCPM trend in the field of resource management.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.381-386
• /
• 2007

The present study is concerned with the application of Constant arc-length method that proposed by Crisfield in the investigation of the geometrically nonlinear behaviour of spatial structures composed by truss or beam element. The arc-length method can trace the full nonlinear equilibrium path of Spatial structure far beyond the critical point such as limit or bifurcation point. So, we have developed the constant arc-length method of Crisfield to analysis spatial structure. The finite element formulation is used to develop the 3d truss/beam element including the geometrical nonlinear effect. In an effort to evaluate the merits of the methods, extensive numerical studies were carried out on a number of selected structural systems. The advantages of Constant arc length method in tracing the post-buckling behavior of spatial structures, are demonstrated.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.11a
• /
• pp.221-224
• /
• 2006

For structural engineers, design of pile cap causes difficulties since design of this member is not specifically addressed by codes. In general, pile cap is considered as deep beam and designed for shear and moment at specified critical section. This is called as traditional section method. However, many international design codes suggest the application of strut tie method for better design of this member. In this paper, a brief application of strut tie method to the design check of pile cap structure designed by section method is presented. Unlike well known pile cap with single column, the example pile cap has two columns. In order to find out proper load path under various load condition, three dimensional finite element method was carried out. The result indicates that provided reinforcement by traditional section method has sufficient capacity to meet the design requirements.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.4
• /
• pp.774-780
• /
• 2017

This paper proposes an efficient binary arithmetic encoder hardware architecture for CABAC encoding, which is an entropy coding method of HEVC. CABAC is an entropy coding method that is used in HEVC standard. Entropy coding removes statistical redundancy and supports a high compression ratio of images. However, the binary arithmetic encoder causes a delay in real time processing and parallel processing is difficult because of the high dependency between data. The operation of the proposed CABAC BAE hardware structure is to separate the renormalization and process the conventional iterative algorithm in parallel. The new scheme was designed as a four-stage pipeline structure that can reduce critical path optimally. The proposed CABAC BAE hardware architecture was designed with Verilog HDL and implemented in 65nm technology. Its gate count is 8.07K and maximum operating speed of 769MHz. It processes the four bin per clock cycle. Maximum processing speed increased by 26% from existing hardware architectures.