• Journal of Environmental Science International
• /
• v.7 no.4
• /
• pp.523-530
• /
• 1998

Precipitation samples were collected at sixteen sites in Northeast Asia from June 1995 to February 1997, and were analysed for the anions $SO_4^{2-}$, $NO_3^-$and $Cl^-$ and for the cartons $Na^+, NH_4^+, K^+, Mg^{2+} and $Ca^{2+}$in addition to pH and conductivity measurements. The quality assurance of chemical composition data was checked by considering the ion balance evaluating by 1 h 1 value and the conductilfty balance. The sum of cation concentrations were slightty greater than the sum of anion concentraions. For the anions, $SO_4^{2-}$ clearly dominates in most of sampling states whereas $Cl^-$ is more abundant in coast and rural sites In. Tapan. For the cations. $Ca^{2+}$ and $NH_4^+$ are generally the more abundant tons except when sources of Na+ exist. The contribution rate of nss-$SO_4^2-and NO_3^-$ to acidity are about 70% and 10-30%. respectively. The neutralizing capacity by a major neutralizing cations such as $NH_4^+$ and nuts -$SO_4^2$. are above 98%(heavy polluted and urban sites in China), above 70%(urban sites in Japi,n and in Korea, coast sites In Chinas and above 60%(rural sites in Japan and in Korea), respectively.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.8
• /
• pp.883-887
• /
• 2010

3D face tracking is one of essential techniques in computer vision such as surveillance, HCI (Human-Computer Interface), Entertainment and etc. However, 3D face tracking demands high computational cost. It is a serious obstacle to applying 3D face tracking to mobile devices which usually have low computing capacity. In this paper, to reduce computational cost of 3D tracking and extend 3D face tracking to mobile devices, an efficient particle filtering method using MLESAC(Maximum Likelihood Estimation SAmple Consensus) motion estimation is proposed. Finally, its speed and performance are evaluated experimentally.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.3
• /
• pp.389-396
• /
• 2001

In detection of a scene change of the moving pictures which has massive information capacity, the temporal sampling method has a faster searching speed and lower missing scene change detection than the sequential searching method for the whole moving pictures, yet employed searching algorithm and detection interval greatly affect missing frame and searching precision. In this study, the whole moving pictures were primarily retrieved threshold by the temporal difference of histogram scene change detection method. We suggested a dynamic threshold algorithm using cut detection interval and derived an equation formula to determine optimal primary retrieval threshold which can cut detection interval computation. Experimental results show that the proposed dynamic threshold algorithm using cut detection interval method works up about 30 percent in precision of performance than the sequential searching method.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.23-26
• /
• 2001

Batch test and column test were performed to develop the design factors for PRBs against the contaminated groundwater by ammonium and lead. Clinoptilolite, one of the natural zeolites having excellent cation exchange capacity(CEC), was chosen as the reactive material through the ion-exchange mechanism. In the batch test, the reactivity of Clinoptilolite to ammonium and lead was examined with varying the particle size of Clinoptilolite. The nit weight of Clinoptilolite showed removal efficiencies of 65 % against the ammonium and 98% against lead. The effect of particle size of Clinoptilolite was not noticeable. In the column test, the permeability was examined using flexible-wall permeameters with varying the particle size of Clinoptilolite. When the washed Clinoptilolite having the diameter of 0.42-0.85 nm was mixed with Jumunjin sands in 20:80 ratio (w/w), the highest permeability of 2$\times$10$^{-3}$ -7 x 10$^{-4}$ cm/s was achieved. The reactivity and the strength property of the mixed material were investigated using fixed wall column having 8 sampling ports on the wall and the direct shear test, respectively. Clinoptilolite was found to be a suitable material for PRBs against the contaminated groundwater with ammonium and/or heavy metals.

• Korean Journal of Health Education and Promotion
• /
• v.33 no.5
• /
• pp.107-119
• /
• 2016

Objectives: This study aims at examining the association of sense of community with community participation for health promotion in urban areas of Korea. Methods: We analyzed data from 'Community Capacity for Healthy Gangdong Communites' Survey' in 2007. The survey was based on self-reported questionnaires, which were distributed to 1,800 community residents over the age of nineteen in five administrative communities of Gangdong-gu, Seoul, in Korea by using proportionate probability sampling method. We measured 'Sense of community' with four indicators including 'Good neighborhoods', 'Perceived possibility of cooperation', 'Pride of community' and 'Possibility of development' by using 5-point Likert scales. Community participation was measured with the experience rate or the extent of participation by 5-point Likert scales in seven community actions or activities including voting, community program planning, social actions, etc. We examined the association of sense of community with community participation by using regression analyses. Results: This study has shown that sense of community was associated with and made positive impacts on community participation in diverse community actions or activities in urban communities. Conclusions: For promoting community health in urban areas, we can increase community participation more effectively with the efforts of enhancing sense of community.

• Journal of the Korean Geosynthetics Society
• /
• v.8 no.2
• /
• pp.1-9
• /
• 2009

When some structures are constructed over the sanitary landfill, the waste should be treated by means of replacement and other ways. Otherwise, various problems like a ground contamination, settlement, reduction of bearing capacity and others may be generated. To find out the optimal method of treatment, the properties of the ground have to be inspected. In this study, the preliminary investigation was conducted to find out the characteristic of this site which is considered as insanitary waste landfill. Furthermore, the shape and the amount of the waste was investigated by subsurface investigation like a boring and sampling methods. In addition, the degree of ground contamination and disposal method of refuse was examined.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.2 no.3
• /
• pp.36-47
• /
• 2003

Wideband Code Division Multiple Access (WCDMA) is one of the air interface techniques proposed for the third generation (3G) mobile communication system. WCDMA was selected because it fulfills the IMT-2000 requirements for higher data rate trans mission, support of multimedia capabilities and other flexible services due to its variable bit rates and larger bandwidth, improved capacity and coverage, efficient power control and support for advanced and improved detector structures. Performance evaluation of 3G wireless network through simulation plays an important role in the design and implementation of the actual system, aiding the wireless system designer by providing them the necessary performance conformance statistics prior to implementation. In accordance with this goal, a simulator engine was developed entirely on a MATLAB platform to emulate the behaviour of the WCDMA air interface for both the uplink and downlink in a real world fading mobile environment. This paper discuss the development of the simulator along with a brief description of its functionalities and user interface. The WCDMA air interface mode focused in this paper is in accordance to the 3GPPs frequency division duplex (FDD) mode and restricted to the physical layer description. Performance results for the selected cases for the downlink, uplink, varying mobile velocity and sampling rates are also provided.

• Journal of the Korea Society for Simulation
• /
• v.20 no.3
• /
• pp.49-58
• /
• 2011

The workloads of facilities and laborers are important for the capacity planning in a factory. They are always referenced whenever a factory develops a new product, increases the production quantity and makes a plan of new investment. There are many measuring methods for estimating the workload effectiveness of facilities and laborers. In this paper, various measuring methods including survey, work sampling, micro-motion study, data gathering from ERP system and simulation, are analyzed for comparing the accuracy of workload. This case study is conducted in a Korean company that produces semiconductor parts like leadframe and packaging substrate.

• Progress in Superconductivity and Cryogenics
• /
• v.23 no.4
• /
• pp.25-29
• /
• 2021

For the application of HTS wire to AC power equipment, a conductor with high current capacity and low loss is required. CORC^®, one of the high-current conductors manufactured using several HTS wires, is made by winding the wires in a spiral on a cylindrical former. Because the magnetization loss of a CORC^® conductor depends on the degree of magnetic coupling between the wires constituting the CORC^®, it is necessary to know the value of the magnetization loss of the CORC^® itself. In order to obtain an accurate loss value, it is necessary to know the effect of the ratio of the winding pitch of the CORC^® conductor in the pickup coil region sampling the magnetization loss signal. To confirm this effect, we prepare CORC^® samples having various winding pitches, and measure and compare the magnetization losses. In addition, the magnetization loss was measured while rotating the CORC^® samples and it was examined whether there was a difference in the magnetization loss according to the rotation.

• Journal of Power Electronics
• /
• v.19 no.4
• /
• pp.1034-1044
• /
• 2019

In medium-voltage and high-voltage high-power converters, the switching devices need to operate at a low switching frequency to reduce power loss and increase the power capacity. This increases the delay of the signal sampling and PWM. It also makes the cross-couplings of the d-q current components more severe. In addition, the LCL filter has three cross-coupling loops and is prone to resonance. In order to solve these problems, this paper establishes a complex vector model of an LCL type grid-connected converter. Based on this model, two multiple decoupling current control strategies with passive damping / notch damping are proposed for the LCL type grid-connected converter. The proposed strategies can effectively eliminate the cross-couplings of the converter, achieve independent control of the d-q current components, expand the stable region and suppress the resonance of the LCL filter. Simulation and experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed strategies.