• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.87-96
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• 1999

To analyze the dynamic behavior of structure, direct integration and mode superposition may be utilized in time domain analysis. As finite number of frequencies can give relatively exact solutions, mode superposition is preferable in analyzing structural behavior. In non-linear analysis, however, mode superposition is seldom used since time-varying element stiffness changes stiffness matrix, and the change of stiffness matrix leads to the change of essential constants - natural frequencies and mode shapes. In spite of these difficulties, there are some attempts to adopt mode superposition because of low cost compared to direct integration, but the result is not satisfactory. In this paper, a method using mode superposition in non-linear analysis is presented by separating local element stiffness from global stiffness matrix with the difference between linear and non-linear restoring forces to the external force vectors included. Moreover, the hysteresis model changing with the relative deformation in each floor makes it possible to analyze non-linear behavior of structure. The proposed algorithm is applied to shear beam model and the maximum displacement is compared with the result using direct integration method.

• Korea journal of population studies
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• v.20 no.1
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• pp.27-46
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• 1997

It is generally known that the quality of Korean population census results is very high. The completeness of the census has been over 97% since 1960. The age errors are very low and they belong to the lowest group in the world. However, Korean census has several problems to be solved, which are suggested as the followings: 1) Since most Koreans are basically educated, we will be able to adopt the self-reporting survey method for the next census instead of the interview method. Then, we can save a lot of time and cost in a census. 2) We have to simplify, the items of age since the effects of the four age items (Korean ago, zodiac year at birth, birth date in solar or lunar calendar) are not large enough to compare to the investments of manpower and costs. 3) It should be helpful to improve the quality of census data if the post enumeration survey is conducted more successfully and the results evaluated for more items not only age are published. 4) For the reduction of the error rates for the age groups of infants, young children and the young labours who are moving frequently, we need some special items for the compliteness of the population census by age group. 5) We have to prepare and release the 1995 2% sample data file to the public users for the improvement of the usefuleness in time. Furtheremore, it is also very important for the research in the field of social sciences that the back series of 2% sample files from 1985 census data are reconstructed.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.437-447
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• 2020

The purpose of this study is to research the countermeasures and expected effects through the use of drones in the field of disaster prevention as a drone-based smart quarantine performance method. The environmental, market, and technological approaches to the review of the current quarantine performance task and its countermeasures are as follows. First, in terms of the environment, the effectiveness of the quarantine performance business using drone-based control is to broaden the utilization of forest, bird flu, livestock, facility areas, mosquito larvae, pests, and to simplify and provide various effective prevention systems such as AI and cholera. Second, in terms of market, the standardization of livestock and livestock quarantine laws and regulations according to the use of disinfection and quarantine missions using domestic standardized drones through the introduction of new technologies in the quarantine method, shared growth of related industries and discovery of new markets, and animal disease prevention It brings about the effect of annual budget savings. Third, the technical aspects are (1) on-site application of disinfection and prevention using multi-drone, a new form of animal disease prevention, (2) innovation in the drone industry software field, and (3) diversification of the industry with an integrated drone control / control system applicable to various markets. (4) Big data drone moving path 3D spatial information analysis precise drone traffic information ensures high flight safety, (5) Multiple drones can simultaneously auto-operate and fly, enabling low-cost, high-efficiency system deployment, (6) High precision that this was considered due to the increase in drone users by sector due to the necessity of airplane technology. This study was prepared based on literature surveys and expert opinions, and the future research field needs to prove its effectiveness based on empirical data on drone-based services. The expected effect of this study is to contribute to the active use of drones for disaster prevention work and to establish policies related to them.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.693-705
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• 2020

Grapes (Vitis spp. L.) are the third most produced fruit in the world. Crown gall disease caused by Agrobacterium vitis forms galls in the stems of the grapevines and reduces the vitality of the fruit trees, resulting in reduced yields. This pathogen has occurred in vineyards worldwide and caused serious economic losses. It is a soil-borne disease, so Agrobacterium vitis can survive for several years in vineyards and is difficult to control. Additionally, since there is no effective chemical control method, the most effective control method is the breeding of resistant varieties. To make the resistant variety, marker-assisted selection (MAS) enables fast breeding with low cost. In this study, we applied a genome-wide association study (GWAS), by combining phenotyping and genotyping-by-sequencing (GBS), for the development of a single nucleotide polymorphism (SNP) marker set related to crown gall disease using 350 grapevine varieties. As a result of the GBS based genotyping analysis, about 58,635 SNPs were obtained. In addition, the phenotypic analysis showed 35.2% resistance, 73% moderate susceptibility and 16.4% highly susceptibility. Moreover, after confirmation, two genes (VvARF4 and VvATL6-like) were shown to be related to crown gall disease based on the results of GWAS analysis, using the phenotypic data, and GBS. High-resolution melting analysis (HRMA) was performed using the Luna^® Universal Probe with real-time PCR to distinguish the melting peaks of the resistant and susceptible varieties. Our data show that these SNP markers are expected to be helpful in evaluating resistance against grapevine crown gall disease and in breeding.

• Journal of Korea Water Resources Association
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• v.44 no.5
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• pp.377-388
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• 2011

Surface Image Velocimetry (SIV) is a recently-developed discharge measurement instrument. It uses image processing techniques to measure the water surface velocity and estimate water discharge with given cross section. The present study aims to implement a FSIV (Fixed-type Surface Image Velocimetry) at Soojeon Bridge in the Dalcheon. The hardware system consists of two digital cameras, a computer, and a pressure-type water stage gauge. The images taken with the hardware system are sent to a server computer via a wireless internet, and analyzed with a image processing software (SIV software). The estimated discharges were compared with the observed discharges through Goesan dam spillway and index velocity method using ADVM. The computed results showed a good agreement with the observed one, except for the night time. The results compared with discharges through Goesan dam spillway reached around 5~10% in the case of discharge over 30 m3/s, and the results compared with discharges through index velocity method using ADVM reached around 5% in the case of discharge over 200 $m^3/s$. Considering the low cost of the system and the visual inspection of the site situation with the images, the SIV would be fairly good way to measure water discharge in real time.

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.62-70
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• 2014

An apartment house, a private facility, is a house built for many persons to live independently in a building. An apartment house is a building where life damage can happen most in case of a safety accident due to insufficient inspections. However, formal inspections are being realized due to awareness shortage of managing bodies about safety inspection and low-price order-receiving of diagnosing enterprises via the lowest bidding method. This is because it is judged that remarkable costs are inputted in repairs and reinforcement such as maintenance of a structure and that there is a large possibility of human damage in case of a safety accident in a structure. So, this paper aims to derive the points to improve in the current criterion to execute an efficient detailed inspection. As its method, the design price and execution price situation of 66 buildings inspected in detail for recent 3 years for the class 2 facilities in Gwangju Metropolitan City and Jeonranam-do are examined and analyzed. The state2 object buildings to inspect are selected through this. And this paper aims to present the points to improve through the analysis of current problems by evaluating the detailed inspection report and the detailed inspection execution price calculation criterion for the selected 10 apartment houses.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.12-20
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• 2018

As facilities have become larger, more complex, and advanced, the importance of the facility management in the operation phase of the building is increasing. As a result, the scope of the facility management function is expanding, and the requirements of information are ever-increasing. However, inefficient exchange of information occurs due to duplicated tasks and lack of collaboration among the construction life cycle phases, resulting in cost loss. These low interoperability issues can be complemented by construction information management from a life cycle perspective. Efficient construction information management at each life-cycle stage is derived from the owner's will and is materialized through the construction information handover requirements by the owner. The purpose of this study is to develop an evaluation method of construction information handover requirements for facility management. In order to develop the method, facility management types and business functions are also classified and defined in this paper. Using the methodology proposed by this study, a case-study of evaluating the 'takeover items' submitted by contractors was performed for the purpose of research validation. The results of the case-study found that the most effective areas are in the order of 'legal informations', 'drawings', 'guides', etc. This study can be used as a reference data for deriving handover requirements for construction information at the early stage of the project.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.148-154
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• 2005

As the exciting point of each phase is determined by the position of rotor, the rotor's accurate position-information is needed for the Switched Reluctance Motor(SRM). When using an absolute-encoder or a resolver, to detect the location of rotor the initial starting is possible, as early sensing of rotor's location is possible. However, this is not appropriate, considering the economical efficiency, and in case of using the incremental-encoder, there's a problem at initial starting as it is not easy to track down the location of rotor at the very beginning. When using Hall-ICs, there's a fault, as it needs a special ring magnet. Considering the initial starting and economical efficiency, the optical sensor technique using a slotted-disk and an opto-interrupter is appropriate, however, this method needs three opto-interrupters and a slotted-disk when using the 6/4 pole SRM. Nevertheless, in this paper, it used only two optical sensors to operate 6/4 pole SRM and made the start up and also forward and reverse operation possible. By excluding the slotted-disc md shortening a optical sensor, it improved the convenience and economical efficiency of the production. Also, as the space for slotted-disc is no more needed, it was able to reduce the size of motor.

• Environmental Engineering Research
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• v.13 no.3
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• pp.125-130
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• 2008

Free ammonia ($NH_3$-N) inhibition of nitrite-oxidizing bacteria (NOB) has been widely studied for partial nitrification (or nitrite accumulation) and denitrification via nitrite ($NO_2^-$-N) as a low-cost treatment of ammonium containing wastewater. The literature on $NH_3$-N inhibition of NOB, however, shows disagreement about the threshold $NH_3$-N concentration and its degree of inhibition. In order to clarify the confusion, a simple and cheap respirometric method was devised to investigate the effect of free ammonia inhibition of NOB. Sludge samples from an autotrophic nitrifying reactor were exposed to various $NH_3$-N concentrations to measure the maximum specific nitrite oxidation rate ($\hat{K}_{NO}$) using a respirometer. NOB biomass was estimated from the yield values in the literature. Free ammonia inhibition of nitrite oxidizing bacteria was reversible and the specific nitrite oxidation rate ($K_{NO}$) decreased from 0.141 to 0.116, 0.100, 0.097 and 0.081 mg $NO_2^-$-N/mg NOB h, respectively, as the $NH_3$-N concentration increased from 0.0 to 1.0, 4.1, 9.7 and 22.9 mg/L. A nonlinear regression based on the noncompetitive inhibition mode gave an estimate of the Inhibition concentration ($K_I$) of free ammonia to be 21.3 mg $NH_3$-N/L. Previous studies gave $\hat{K}_{NO}$ of Nitrobacter and Nitrospira as 0.120 and 0.032 mg/mg VSS h. The free ammonia concentration which inhibits Nitrobacter was $30{\sim}50\;mg$ $NH_3$-N/L and Nitrospira was inhibited at $0.04{\sim}0.08\;mg$ $NH_3$-N/L. The results support the fact that Nitrobacter is the dominant NOB in the reactor. The variations in the reported values of free ammonia inhibition may be due to the different species of nitrite oxidizers present in the reactors. The respirometric method provides rapid and reliable analysis of the behavior and community of the nitrite oxidizing bacteria.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.33-43
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• 2014

Recently, the case to construct the structure on the soft clayey ground has increased and in order to the reduction of the cost of construction and maintenance on the social infrastructure facilities we have been trying to improve the soft clayey ground using the existing methods such as the pre-loading method and the vertical drain method. Like this, when various ground improvement methods are applied on the soft clayey ground, a long-term consolidation settlement will be key issue due to low permeability coefficient of cohesive soil. According to existing research results that relate to the consolidation settlement, the loading periods for existing the standard consolidation test (Oedometer test) to obtain the consolidation parameters are needed for minimum ten days or more. Therefore, in this study, the standard consolidation test (24 hours step-loading) and constant strain rate consolidation test changed by strain rate was performed using the remolded marine clay on Gwangyang bay composed of a soft clayey ground of the south-west coast. From the laboratory test results, the characteristics of compression, strain-effective stress relations by constant strain rate and the variation characteristic of the pore water pressure by different of loading speed and the relation between consolidation parameters and constant strain rate are compared and analyzed.