• The Transactions of the Korean Institute of Power Electronics
• /
• v.17 no.3
• /
• pp.274-280
• /
• 2012

In this paper, three current controllers for a grid-connected PCS using an LCL filter are compared and analyzed. Current controllers discussed in this paper are linear controllers such as PI (proportional-integral), PR (proportional-resonant), and DB (deadbeat) controller. Both transient and steady state responses of each controller are compared through both simulation and experiment. Although the DB controller has the fastest transient response and the lowest THD in the steady state, the DB controller has two cycles delay of current response in the steady state and has the stability problem which can be occurred due to variation of the system parameters. On the one hand the responses of PR controller are not much different from that of DB controller but the other hand that are not only strong to noise of grid current but also have smaller THD than PI controller. Considering the response time and stability issue of three controllers, the PR controller has the best performance among three controllers and thus can be strongly recommended as a current controller for a grid-connected PCS.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.5
• /
• pp.350-354
• /
• 2009

To optimize the performance of software programs, it is important to know certain hardware parameters such as the CPU speed, the cache size, the number of TLB entries, and the parameters of the memory subsystem. There exist several ways to obtain the values of various hardware parameters. Firstly. the values can be taken from the hardware manual. Secondly, the parameters can be obtained by calling functions provided by the operating systems. Finally, hardware detection programs can find the desired values. Such programs are usually executed on PC or server systems and report the CPU speed, the cache size, the number of TLB entries, and so on. However, they do not sufficiently detect the parameters of one of the most important parts of the computer concerning performance, namely the memory bank layout in the memory subsystem. In this paper, we present an algorithm to detect the memory bank parameters. We run an implementation of our algorithm on various embedded systems and compare the detected values with the real hardware parameters. The results show that the presented algorithm detects the cache size, the number of TLB entries, and the memory bank layout with high accuracy.

• Journal of Service Research and Studies
• /
• v.3 no.2
• /
• pp.19-32
• /
• 2013

An explosive growth of mobile devices and smart phones, such as Tablet PC using wireless Internet, is changing the Information environment rapidly. Smart technology telecommuting work or smart work centers, mobile devices, and configure your environment to take advantage of remote collaboration. Also, you do not have the limitations of time and space provides a flexible working environment. Smartwork environment is an IT environment to be provided to carry out the business by accessing remotely via smart device outside of the internal IT infrastructure of an existing. Smartwork system to increase the work efficiency is present to what information protection threats according to their convenience. Safeguards information that can be utilized to build a secure smartwork environment is required. Therefore, in this paper, we examined the worksmart information protection measures that can protect the information be reconciled smoothly to fit the smartwork environment.

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.39 no.1
• /
• pp.7-15
• /
• 2002

This paper is concerned with remote environment monitoring & control for the breeding house as scattering far and wide. The environment data is detected in the breeding house that is collected to one processor. It's adapted to the PSTN(public switch tele-phone network) and multi-processing for exchange the environment data and the control data in between the manager and a breeding house by micro-processor. We have designed the algorithm of the communication sequence through the experimental research. This system is composed of sensor interface, FSK communications, LED display, data latch and MCS-51 single-chip. The S/W is composed with data acquisition by multi-processing, data communication and interrupt. And this paper is Proposed the DB structure algorithm concern to a mount scale using web design. The subject is a performance of effective management for the breeding house.

• The korean journal of orthodontics
• /
• v.21 no.1 s.33
• /
• pp.17-29
• /
• 1991

The purpose of this study was to provide quantitative data describing the effect of rapid palatal expansion (RPE) on nasal airway resistance (NAR). RPE is an orthopedic procedure which is commonly used to widen the maxilla in skeletal Class III patients. 18 subjects (9 males and 9 females, mean age: 10 years 7 months) were selected from the Orthodontics in Yongdong Severance Hospital. Recordings of NAR were taken by active anterior method prior to expansion, immediately after desired maximum expansion, and after approximately 3 months and 6 months, and 1 year. All data was recorded and statistically processed with the SPSS program of IBM PC system. The results are as followings . 1. The average initial NAR of the subjects was 3.84 cm $H_2O/LPS\;(SD{\pm}1.34)$. It was greater than the average NAR of the normal subjects. 2. Among 18 subjects, 9 subjects showed reduction of NAR and 9 subjects showed no specific change of NAR after expansion. 3 An average reduction in NAR after immediately expansion was statistically significant at the 0.05 level. 4. The reduction appeared stable throughout the post treatment observation period of 1 year after expansion. From these results, it was suggested that RPE is a useful method to reduce NAR.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.38 no.5
• /
• pp.58-64
• /
• 2001

Recently many informations are transmitted ,md stored as video data, and they are on the rapid increase because of popularization of high performance computer and internet. In this paper, to retrieve video data, shots are found through analysis of video stream and the method of detection of key frame is studied. Finally users can retrieve the video efficiently. This Paper suggests a new feature that is robust to object movement in a shot and is not sensitive to change of color in boundary detection of shots, and proposes the characterizing value that reflects the characteristic of kind of video (movie, drama, news, music video etc,). The key frames are pulled out from many frames by using the local minima and maxima of differential of the value. After original frame(not de image) are reconstructed for key frame, indexing process is performed through computing parameters. Key frames that arc similar to user's query image arc retrieved through computing parameters. It is proved that the proposed methods are better than conventional method from experiments. The retrieval accuracy rate is so high in experiments.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.47 no.2
• /
• pp.48-53
• /
• 2010

RC(Remote Control) is a technology that can efficiently control and transfer a variety of user commands to CEs. However, the existing RCs have been required various additional features such as communication between CEs, extension of communication range, low power-consumption and bi-directional communication according to the advent of new types of CE devices and its enhanced performance. Even though RC controller has many customers' requests, it is not a simple solution because most legacies work on IR-based RC. In this paper, we propose RF4CE-based Universal Remote Control Framework using Smartphone in order to solve the many constraints of IR legacies. The proposed R-URC system is designed by RF4CE platform which is a kind of de-facto standard for CE remote control communication. From the verification scenarios using various CEs and smart phone, we can see that the proposed R-URC shows the good practical usage in terms of contents sharing and smart CE control.

• Journal of Digital Contents Society
• /
• v.16 no.2
• /
• pp.245-255
• /
• 2015

As people are highly interested in health, the number of people who participate in various sports programs is getting increased. But there is no web service which integrates all the information of the public sports facilities in Seoul and it's convenient to use the public sport facilities. So we propose an integrated information system whoever can find the public sports facilities in Seoul. The public APIs for the Seoul public sports facilities provided by Seoul city are used to integrate the information. Also, our web page provides various graphic function using pictures and videos of the facilities on the environment of HTML5. And it is the responsive webpage which can be provided on both desktop and mobile environment. By implementing the wizard page, the managers of the facilities who are not specialized can renew the information about their facilities easily. And for the easier searching, we provides three options of searching: local, subjects, themes.

• Wind and Structures
• /
• v.20 no.2
• /
• pp.213-236
• /
• 2015

For high-speed railways (HSR) in wind prone regions, wind barriers are often installed on bridges to ensure the running safety of trains. This paper analyzes the effect of wind barriers on the running safety of a high-speed train to cross winds when it passes on a bridge. Two simply-supported (S-S) PC bridges in China, one with 32 m box beams and the other with 16 m trough beams, are selected to perform the dynamic analyses. The bridges are modeled by 3-D finite elements and each vehicle in a train by a multi-rigid-body system connected with suspension springs and dashpots. The wind excitations on the train vehicles and the bridges are numerically simulated, using the static tri-component coefficients obtained from a wind tunnel test, taking into account the effects of wind barriers, train speed and the spatial correlation with wind forces on the deck. The whole histories of a train passing over the two bridges under strong cross winds are simulated and compared, considering variations of wind velocities, train speeds and without or with wind barriers. The threshold curves of wind velocity for train running safety on the two bridges are compared, from which the windbreak effect of the wind barrier are evaluated, based on which a beam structure with better performance is recommended.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.03a
• /
• pp.343-358
• /
• 2008

Piles of a bridge pier are connected with a column through a pile cap(footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. This difference causes a change of the design method. Connection methods between pile heads and the pile cap are divided into two groups ; rigid connections and hinge connections. KHBDC(Korea Highway Bridge Design Code) has specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However some specifications prescribe that conservative results through investigations for both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which have very good quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) are unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the very large diameter drilled shaft and the pile cap for Incheon Bridge which will the longest bridge in Korea were investigated through the full modeling for rigid connection conditions.