• Korean Journal of Environmental Agriculture
• /
• v.19 no.2
• /
• pp.177-182
• /
• 2000

Removal rate of swine wastewater containing organic matter was 99 percent in case of high loading rate. The studies of swine wastewater treatment aim to development of process using soil microorganism. Microorganism was devoted to improve the treatment efficiency of the process. Biochemical oxygen demand (BOD) concentration of treated swine wastewater was under 150 mg/L in anaerobic reactor. Also, value of km and Y were $0.73\;hr^{-1}$ and 0.433 g/VSS/g BODrm/d at microorganism of post aeration tank in anaerobic reactor.

• Journal of ILASS-Korea
• /
• v.22 no.1
• /
• pp.8-12
• /
• 2017

Recently, manufacture and sales of passenger car with GDI (Gasoline Direct injection) were dramatically increased in Korea. In this study, investigation on the exhaust emission characteristics of GDI vehicles according to mileage were conducted by using chassis dynamometer and emission analyzer. Test cars selected 5 types with G4FD engine (1600 cc) and emissions of total 14 vehicles analyzed. Measurement and evaluation on emissions (CO, NOx, NMOG, $CO_2$) characteristics of GDI vehicles with mileages from 40,000 to 80,000 km in certification driving cycle (CVS-75) were carried out in this study. It is revealed that emission results of all test cars shows below emission standard, NMOG emission value of about 80,000 km doubled that of 40,000 km and emission increased by accumulated mileage. Also, increasing pattern of NOx emissions shows when the vehicle mileages was increased and $CO_2$ emission increasing trend obviously do not show according to mileages.

• Journal of the Optical Society of Korea
• /
• v.20 no.5
• /
• pp.567-574
• /
• 2016

We propose a highly birefringent and dispersion compensating photonic crystal fiber based on a double line defect core. Using a finite element method (FEM) with a perfectly matched layer (PML), it is demonstrated that it is possible to obtain broadband large negative dispersion of about -400 to -427 ps/(nm.km) covering all optical communication bands (from O to U band) and to achieve the dispersion coefficient of -425 ps/(nm.km) at 1.55μm. In addition, the highest birefringence of the proposed PCF at 1.55 μm is 1.92 × 10^-2 and the value of birefringence from the wavelength of 1.26 to 1.8 μm (covering O to U bands) is about 1.8 × 10^-2 to 1.92 × 10^-2. It is confirmed that from the simulation results, the confinement loss of the proposed PCF is always less than 10^-3 dB/km at 1.55 μm with seven fiber rings of air holes in the cladding.

• Journal of the Korean Society of Safety
• /
• v.25 no.2
• /
• pp.78-83
• /
• 2010

An installation of automated speed enforcement system(ASES) was known for traffic safety and accident preventive effects that traffic characteristics transmute by speed distribution stabilizing. This study is verified the variations of average speed, 85% speed, speed distribution and dispersion as traffic characteristics depend on enforcement system influences in the road. We tested selected 5 areas. By and large, it has a little differences depend on road geometric structure and traffic environment but that is not too much. After all, after automated speed enforcement system installed in all of test areas, average speed, 85% accumulated speed, speed distribution and dispersion characteristics were declined and equalized. The speed dispersion was smaller than before installed the ASES. The speed dispersion value of each case that is the limited speed has been 70Km/h, 80Km/h at flat and straight, 80Km/h at downhill and straight or downhill and left-curved area was 77.3%, 65.2%, 68.7% and 54.1%. Each of the data was declined. We could analyze that average speed distributed depletion factor was declined rapidly by 66.3% in test area.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.12
• /
• pp.1789-1795
• /
• 2015

The pulley-type tensioning device subjected to a maximum tension of 34 kN has been developed for 400 km/h high-speed railway. The tensioning device is to maintain the tension variation within 3% of the normal value, irregardless of temperature changes. Field tests shows that the tensioning device had a variation of tension which was as small as 0.6% as temperatures changed from $-5{\sim}7^{\circ}C$. Along with the tensions, we measured its X and Y movements due to the temperature changes. Based on a combination of its X and Y movements, we proposed a new performance index with which we can see if the tensioning device has troubles in operation without tension measurements.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.26 no.3
• /
• pp.288-296
• /
• 1998

Natural or human disturbances cause landscape changes, which may be measured by the degree of heterogeneity. In a 16km$\times$19km area, divided into 100m$\times$100m cells, of Seoul city and its suburb, land covers are classified into 6 groups in aerial photos and land use maps. The degree of heterogeneity is defined as the number of cells that surround a central cell but have different land cover from the central cell divided by 8. The value of the degree of heterogeneity is between 0 and 1. Major findings are 1) Both urban and natural areas have low degree of heterogeneity, about 0.15~0.17. 2) Suburban area under heavy pressure of development and urbanization has highest degree of heterogeneity, about 0.25. 3) The peak of the degree of heterogeneity moved about 4.5km outward in 22 years. 4) Outer suburban area has lower degree of heterogeneity as the area is a greenbelt or forest. 5) The results show the areas with higher degree of heterogeneity which may need landscape management plans, and natural areas with lower degree of heterogeneity which may need landscape conservation plans. A landscape change model may be built for a specific city when this technique is applied to multiple sectors of the city, and the model may predict future landscape changes of the city.

• Korean Journal of Remote Sensing
• /
• v.37 no.1
• /
• pp.139-151
• /
• 2021

By the end of December 2020, an earthquake with Mw about 6.4 hit Sisak-Moslavina County, Croatia. The town of Petrinja was the most affected region with major power outage and many buildings collapsed. The damage also affected neighbor countries such as Bosnia and Herzegovina and Slovenia. As a light of this devastating event, a deformation map due to this earthquake could be generated by using remote sensing imagery from Sentinel-1 SAR data. InSAR could be used as deformation map but still affected with noise factor that could problematize the exact deformation value for further research. Thus in this study, 17 SAR data from Sentinel-1 satellite is used in order to generate the multi-temporal interferometry utilize Stanford Method for Persistent Scatterers (StaMPS). Mean deformation map that has been compensated from error factors such as atmospheric, topographic, temporal, and baseline errors are generated. Okada model then applied to the mean deformation result to generate the modeled earthquake, resulting the deformation is mostly dominated by strike-slip with 3 meter deformation as right lateral strike-slip. The Okada sources are having 11.63 km in length, 2.45 km in width, and 5.46 km in depth with the dip angle are about 84.47° and strike angle are about 142.88° from the north direction. The results from this modeling can be used as learning material to understand the seismic activity in the latest 2020 Petrinja, Croatia Earthquake.

• Asia pacific journal of information systems
• /
• v.14 no.3
• /
• pp.57-75
• /
• 2004

The knowledge management is increasingly an important strategic weapon for sustaining competitive advantage of firms. Firms are undertaking knowledge management initiatives and making significant investments. However, there is relatively little empirical support for the impact of knowledge management on performance of firms. Understanding of the impact of knowledge management, this paper explores how knowledge management strategy influences firms' market value. We examine this issue using event study methodology and evaluate the cumulative abnormal returns for knowledge management strategy announced by firms from 1998 to 2002. The results show that firms' announcements of knowledge management strategy are positively related with firms' market value. Specially, dynamic style-which emphasizes both (i) knowledge reusability through information technologies and (ii) knowledge sharing through informal discussions among employees-has higher performance. This outcome presents empirical support to argument that the emphasis on both tacit and explicit knowledge results in better market value.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.47 no.4
• /
• pp.24-32
• /
• 2019

According to the Ministry of Land, Infrastructure, and Transport, the total area of unexecuted urban planning facilities in Korea is about $1,257km^2$, of which 47% is the unexecuted urban green space and forests. In the case of Seoul, the total area of unexecuted urban planning facilities is about $66km^2$, which is 5.24% of the total unexecuted area in the entire country. In Seoul, approximately 88% of the total unexecuted area is urban green space and forests, which is higher than the national rate. About 92% of the unexecuted urban planning facilities are long-term unexecuted urban planning facilities that are more than 10 years old. This study assessed the economic value of potential ecosystem services, focusing on the regulation service, supporting service, and cultural service, for urban green space and forests of unexecuted urban planning facilities in Seoul by using meta-regression analysis. As a result, the value of the regulation service provided by the urban green space and forests in Seoul was about 16.39 billion KRW, the value of the supporting service was about 5.8 billion KRW, and the cultural service value was about 7.78 billion KRW. The total value of ecosystem services is about 33.93 billion KRW. The values of regulation service and cultural service were the highest, and that was attributed to the characteristics of the downtown area. The significance of this study is to evaluate the value of ecosystem services for unexecuted urban planning facilities in Seoul. The results of this study can be used not only in the process of urban planning or policymaking but also land compensation methods applying the concept of an ecosystem service payment system.

• Journal of Environmental Science International
• /
• v.4 no.2
• /
• pp.245-251
• /
• 1995

Generally, It is Introduced to well-known other models without considering tidal current of the field. The paper presents field measurements and numerical model solving velocity field of Cheonsu Bay by two-dimensional tidal model. It was proved that this scheme is easy to handle complex topography. Computed results is represented characteristics of tidal current for Cheonsu Bay. The results of the study can be summarized as follows ; 1. Tide form number has 0.21 value. Tidal range estimated 630.3 cm on spring, 454.1 cm on mean and 277.9 cm on neap, respectively 2. Tidal current has semi-diurnal form. Distance of traveling observed 16.6 km on flood and 15.5 km on ebb. 3. Tidal velocity showed reversing current. It was found that tidal velocity above 100 cm/sec is about 20 %. 4. Computed results are in good agreement with the observed data. Applying the algorithm to Cheonsu Bay, velocity fields and dry bank phenomena are simulated well in spite of complex topography. 5. An advanced study on the effects of open boundary conditions should be continuously performed.