• Journal of the Korea Furniture Society
• /
• v.20 no.2
• /
• pp.122-135
• /
• 2009

The objective of this work was to research click profile of laminate flooring by comparison of click and bonding laminate floorings, especially base on the click profile shape, bonding strength and international patents. Non-glue locking system has been used since laminate flooring was developed. For the reason of environment and saving installation time, the manufacturer in Europe and USA has developed click profile for laminate flooring. Each manufacturer has patent on each click profile. Although each click profile has good lock strength as shape, Berryand Unilin company's click profile systems showed higher locking strength than others. Korean laminate flooring company pay the fee of patent for using European and American manufacturer's click profile. From this work, we grope Korean style laminate flooring and click profile through research on the click profile shape, bonding strength and patents of European and American manufacturers.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.2
• /
• pp.347-354
• /
• 2000

This paper presents the efficient mechanisms for concurrency control and writing authority control in collaborative writing system are represented by the tree structures which consist of the logical objects and the content objects connected to the terminal objects of trees. For concurrency control, we adopted the approach to extend the multiple-granularity-locking-scheme. This scheme allows us to lock any objects at each level of the hierarchy. We also defined the locking compatibility table by analysing the operations applicable to any objects at each level of the hierarchy. We finally suggest the extended-multiple-granularity-locking mechanism which uses the locking compatibilility table for deciding to lock an object. This scheme gives the benefit to maximize the possibility of concurrent accessing to the shared objects. In addition, we suggest a mechanism for writing authority control which prohibits the Non-Group users from modifying the shared objects based on the concept of Group/Non-Group The proposed mechanism allows us to protect copyright very reasonably.

• Journal of Internet Computing and Services
• /
• v.15 no.1
• /
• pp.63-71
• /
• 2014

Currently many non-traditional application areas such as artificial intelligence and web databases require advanced modeling power than the existing relational data model. In those application areas, object-oriented database (OODB) is better data model since an OODB can providemodeling power as grouping similar objects into class, and organizing all classes into a hierarchy where a subclass inherits all definitions from its superclasses. The purpose of this paper is to develop an OODB concurrency control scheme dealing with multiple inheritance. The proposed scheme, called Multiple Inheritance Implicit Locking (MIIL), is based on so-called implicit locking. In the proposed scheme, we eliminate redundant locks that are necessary in the existing implicit locking scheme. Intention locks are required as the existing implicit locking scheme. In this paper, it is shown that MIIL has less locking overhead than implicit locking does. We use only OODB inheritance hierarchies, single inheritance and multiple inheritance so that no additional overhead is necessary for reducing locking overhead.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.11 no.3
• /
• pp.1-10
• /
• 1991

The paper is concerned with the analysis of laminated composite shell structures using an improved degenerated shell element. In the formulation of the element stiffness, the combined use of three different techniques was made. They are; 1) an enhanced interpolation of transverse shear strains in the natural coordinate system to overcome the shear locking problem; 2) the reduced integration technique in in-plane strains to avoid the membrane locking behavior; and 3) selective addition of the nonconforming displacement modes to improve the element performances. This element is free of serious shear/membrane locking problems and undesirable compatible/commutable spurious kinematic deformation modes. An incremental total Lagrangian formulation is presented which allows the calculation of arbitrarily large displacements. The resulting non-linear equilibrium equations are solved by the Newton-Raphson method. The versatility and accuracy of this improved degenerated shell element are demonstrated by solving several numerical examples.

• IE interfaces
• /
• v.14 no.2
• /
• pp.140-147
• /
• 2001

In the turbine-blade manufacturing industry, turbine-blades are machined and then are assembled to form a circular roll of blades. The roll of blades should be balanced as much as possible, since otherwise the efficiency of the turbine generator might be damaged. A locking blade is a blade whose location is fixed and a non-locking blade is a blade whose location can be freely changed. In this paper, we study methods for balancing the weights of the rotating blades for a turbine where some blades are locking blades. The turbine-blade balancing problem is formulated into a mixed-integer programming problem, which turns out to be NP-hard. A heuristic method based on the number partitioning algorithm is developed and the computational experiments show very promising results.

• Journal of Information Technology Applications and Management
• /
• v.12 no.4
• /
• pp.59-70
• /
• 2005

Flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. in order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient transaction processing. F2Pl improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of F2PL. Based on the results of the performance evaluation, we conclude that F2PL scheme outperforms the traditional scheme.

• Korean Journal of Optics and Photonics
• /
• v.4 no.3
• /
• pp.330-337
• /
• 1993

Figure '8' type, passively-mode-locked erbium-doped-fiber ring laser was developed, incorporating a nonlinear loop mirror. Transmittance of the loop mirror was found to be dependent on the incident light intensity due to the non-reciprocal nonlinear phase shift, which enables the passive mode locking of the laser. Self-starting of stable mode locking was possible with only controlling the polarization controllers inside the cavity without any help of external perturbation or modulation. The mode-locked output pulse shape was discussed in relation with the transmission characteristics of nonlinear loop mirror.

• Computational Structural Engineering
• /
• v.3 no.3
• /
• pp.113-123
• /
• 1990

The paper is concerned with the elasto-plastic and geometrically nonlinear analysis of shell structures using an improved degenerated shell element. In the formulation of the element stiffness, the combined use of three different techniques was made. They are; 1) an enhanced interpolation of transverse shear strains in the natural coordinate system to overcome the shear locking problem ; 2) the reduced integration technique in in-plane strains to avoid the membrane locking behavior ; and 3) selective addition of the nonconforming displacement modes to improve the element performances. This element is free of serious shear/membrane locking problems and undesirable compatible/commutable spurious kinematic deformation modes. In the formulation for plastic deformation, the concept of a layered element model is used and the material is assumed von Mises yield criterion. An incremental total Lagrangian formulation is presented which allows the calculation of arbitrarily large displacements and rotations. The resulting non-linear equilibrium equations are solved by the Netwon-Raphson method combined with load or displacement increment. The versatility and accuracy of this improved degenerated shell element are demonstrated by solving several numerical examples.

• Structural Engineering and Mechanics
• /
• v.59 no.3
• /
• pp.503-526
• /
• 2016

In-plane and out-of-plane free vibration analysis of Timoshenko curved beams is addressed based on the isogeometric method, and an effective scheme to avoid numerical locking in both of the two patterns is proposed in this paper. The isogeometric computational model takes into account the effects of shear deformation, rotary inertia and axis extensibility of curved beams, and is applicable for uniform circular beams, and more complicated variable curvature and cross-section beams as illustrated by numerical examples. Meanwhile, it is shown that, the $C^{p-1}$-continuous NURBS elements remarkably have higher accuracy than the finite elements with the same number of degrees of freedom. Nevertheless, for in-plane or out-of-plane vibration analysis of Timoshenko curved beams, the NURBS-based isogeometric method also exhibits locking effect to some extent. To eliminate numerical locking, the selective reduced one-point integration and $\bar{B}$ projection element based on stiffness ratio is devised to achieve locking free analysis for in-plane and out-of-plane models, respectively. The suggested integral schemes for moderately slender models obtain accurate results in both dominated and non-dominated regions of locking effect. Moreover, this strategy is effective for beam structures with different slenderness. Finally, the influence factors of structural parameters of curved beams on their natural frequency are scrutinized.

• Structural Engineering and Mechanics
• /
• v.14 no.5
• /
• pp.595-610
• /
• 2002

This paper presents an efficiency of various non-conforming (NC) modes in development of a series of new finite elements with the special emphasis on 4-node quadrilateral elements. The NC modes have been used as a key scheme to improve the behaviors of various types of new finite elements, i.e., Mindlin plate bending elements, membrane elements with drilling degrees of freedom, flat shell elements. The NC modes are classified into three groups according to the 'correction constants' of 'Direct Modification Method'. The first group is 'basic NC modes', which have been widely used by a number of researchers in the finite element communities. The basic NC modes are effective to improve the behaviors of regular shaped elements. The second group is 'hierarchical NC modes' which improve the behaviors of distorted elements effectively. The last group is 'higher order NC modes' which improve the behaviors of plate-bending elements. When the basic NC modes are combined with hierarchical or higher order NC modes, the elements become insensitive to mesh distortions. When the membrane component of a flat shell has 'hierarchical NC modes', the membrane locking can be suppressed. A number of numerical tests are carried out to show the positive effect of aforementioned various NC modes incorporated into various types of finite elements.