• The KIPS Transactions:PartA
• /
• v.14A no.4
• /
• pp.235-244
• /
• 2007

Caching and prefetching policies have been used in most of computer systems to compensate speed differences between primary memory and secondary storage devices. In this paper, we design and implement a Flash Cache Core Module(FCCM) on the YAFFS which operates on a file system layer for NAND flash memory. The FCCM is independent of the underlying kernel in order to support its stability and compatibility. Also, we implement the Dirty-Last memory replacement technique considering the characteristics of flash memory, and the waiting queue for pages to be prefetched according to page hit. The FCCM reduced the number of I/Os and the amount of prefetched pages by maximum 55%(20% on average) and maximum 55%(24% on average), respectively, comparing with caching and prefetching policies of Linux.

• Journal of the Korean Geosynthetics Society
• /
• v.3 no.1
• /
• pp.3-15
• /
• 2004

Geogrid reinforced soil structures with segmental block facing have been increased since 1990's, because of the convenience of installation and the flexible appearance. In this paper, the behavior of the segmental reinforced retaining wall was analysed with the results of field monitoring. The height and length of reinforced wall are 12m and 25m, respectively. The field measurement equipments are horizontal and vertical earth pressure cells, settlement plate, strain gauge, inclinometer, and displacement pin. Based on the field monitoring, the horizontal earth pressure was approximately 0.3times higher than that of the theoretical method and the maximum tensile strength of reinforcement was 26.2kN/m. The displacement of facing wall was 23mm at the point of 7.1m height of the wall and toward the wall facing. The results of the study indicate that the segmental reinforced retaining wall is in a stable condition because of good compaction & reinforcement effects, and long period of construction time. Finally, the computer program of SRWall is very useful tool to design the segmental reinforced retaining wall.

• Journal of the Korean association of regional geographers
• /
• v.7 no.2
• /
• pp.97-119
• /
• 2001

The present education situations are rapidly changing to adapt to 'the Knowledge & Information-based Society'. Especially, the implementation of 'the 7th National Curriculum' put strong emphasis on the learner-centered education that refers to the ability grouping. Therefore, it is necessary that the change from a traditional teaching method to a learner-centered one in geography education will take place. This study will present a design of geography ability grouping through the Task-Solving Learning. This ability grouping method is suitable for the large class. And this study also presents a strategy by applying WBI, which make use of the advantage of computer and constructivism. This WBI model can be applied properly to many teaching-learning methods that includes Self-Directed Learning, Collaborate Learning, Ability Grouping, and Applying ICT Instruction. Actually they are demanded in the current education. A geography-classroom will have an accessible internet program as a precondition for this instruction.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.7
• /
• pp.1371-1378
• /
• 2009

We propose a low-power eFuse one-time programmable (OTP) memory cell based on a logic process. The eFuse OTP memory cell uses separate transistors optimized at program and read mode, and reduces an operation current at read mode by reducing parasitic capacitances existing at both WL and BL. Asynchronous interface, separate I/O, BL SA circuit of digital sensing method are used for a low-power and small-area eFuse OTP memory IP. It is shown by a computer simulation that operation currents at a logic power supply voltage of VDD and at I/O interface power supply voltage of VIO are 349.5${\mu}$A and 3.3${\mu}$A, respectively. The layout size of the designed eFuse OTP memory IP with Dongbu HiTek's 0.18${\mu}$m generic process is 300 ${\times}$557${\mu}m^2$.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.2
• /
• pp.1083-1088
• /
• 2014

Recently, due to advances in both imaging technology and ICT, various types of image processing services became available and the application services of these two technologies are diversifying. Recognition of vehicle license plates is used in places where vehicle information is needed such as in parking management. However, existing systems have economic disadvantages like issuing parking tickets and attaching unnecessary equipment. In order to solve these problems, we designed and implemented automatic parking management system through recognition of vehicle license plates by using emguCV that is based on OpenCV. Additionally, we designed improved UI to handle the entire parking management situation which include information such as details of each parking vehicle, parking time and remaining parking spaces without screen movement. This improved UI is implemented with the use of WPF which is the latest technology in user program development. The emguCV used in this paper showed the most optimized performance in Intel based environment. With it, we obtained the result of within 0.5 seconds of recognition processing time and over 90% of recognition rate. Through improved UI, the manager could both simply and intuitively manage the entire system.

• Korean Journal of Optics and Photonics
• /
• v.16 no.4
• /
• pp.334-339
• /
• 2005

We studied the spatial filtering characteristics of a multi-phase hologram optical low-pass filter(HOLF). Using the Monte-Carlo based hologram generation program, we designed holograms whose diffraction patterns are circular shaped 21 beams and calculated the diffraction efficiencies and MTFs. 4-phase HOLF have the same diffraction efficiency as that of 2-phase HOLF. The MTF graphs of the two are also nearly alike. But 8-phase HOLF shows higher efficiency than those previously discussed and has larger MTF values in the low frequency region. 16-phase HOLF has just a little better characteristics than 8-phase. Considering the errors which can arise in the process of making holograms, 8-phase HOLF fits the goal of improving the resolution of spatial filter. We also fabricated 8-phase HOLF and .measured MTF The experimental results agree well with the theoretical expectations.

• Journal of Internet Computing and Services
• /
• v.10 no.6
• /
• pp.159-171
• /
• 2009

The objective of this research is to explore a method to utilize a programmable robot, as a potential learning tool in the elementary school's curricula. Due to their programmability and operational ease of use, programmable robots are among digital toys that today offer specially instructive features. In this research, we developed the robot game-based project contents as a tool for teaching the elementary school children to learn the algorithm, the essential part of computer programming. The LEGO material, selected as the construction kit for robot, consists of a mechanical assembly system, a set of sensors and actuators, a central control unit, a programming environment. The project requires the children to complete 3 separate tasks, each of which is developed based on the principles of algorithm. The classroom feedback supports that the robotic experiences provided the children with fun and absorption. It is likely that implementing learning with robot in regular classroom in elementary school can bring new possibilities to the educational system, provided that a thorough preparation backs up the plan.

• Applied Chemistry for Engineering
• /
• v.9 no.5
• /
• pp.768-773
• /
• 1998

A mathematical model of discharge mechanism of metal-hydride (MH) electrode was presented. A computer simulation program was developed in order to predict the variation of electrode potential and the distribution of hydrogen concentration within MH particles during discharge. By investigating the effects of the discharge current density, the size of MH particle, the diffusivity of hydrogen in MH particle, and the porosity of the electrode, it was found that these factors exerted a collective effect on the discharge characteristic of the electrode and the utilization of hydrogen in the MH particle. It was confirmed that and optimization of design factors of an MH electrode is necessary in order to execute a high-rate discharge and to improve the utilization of hydrogen in MH particle.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.4
• /
• pp.109-120
• /
• 2003

The state-of-art of curved box girder bridge with cross section design has advanced in various area. In these days, several analytical techniques for behaviors of curved box girder bridges cross section are available to engineers. The transfer matrix method is extensively used for the structural analysis because its merit in the theoretical background and applicability. The technique is attractive for implementation on a numerical solution by means of a computer program coded in Fortran language with a few elements. To demonstrate this fact, it gives good results which compare well with finite element method. Therefore, this paper proposed the static analysis method of curved box bridge with cross section by transfer matrix method based on pure-torsional theory and the optimal span ratio/variable cross section ratio of 3 span continuous curved box girder bridge.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.11 no.3
• /
• pp.20-28
• /
• 2007

The easiest way to see the phenomena of compressor surge is to show the static and dynamic operation characteristic on the map. Its operation zone will be restricted by the surge limit and, static and transient process must have some margin for it. Effect of rotor moment of inertia, air/gas volumes and heat transfer are factors to cause the transition from the static line. In case a large volume such as heat exchanger exists in the system it will exert a substantial influence to dynamic characteristics. In the present paper, influence of air volume bled from the compressor exit on transient process is investigated with an example of an auxiliary power unit micro-turbine engine. Turbine mass, pressure ratio, rotation speed, power and moment are calculated based on mass and work conservation. Result from the present study can give guidance to design the control system. A computer program is developed to calculate the dynamic process using the MathCAD commercial software.