• Journal of Forest and Environmental Science
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• v.30 no.4
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• pp.315-321
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• 2014

Forest timber production potential of any site is oftentimes measured quantitatively by site index, which is defined as dominant height of a particular stand at a specified age. A site index was developed for estimating site quality of monoculture Pinus caribaea plantations in southwestern Nigeria using a base age of 25 years. Dominant height data were collected from 60 Temporary Sample Plots (TSPs) of $20{\times}20m$ in plantations of 15 to 37 years. Linear and non-linear models as been widely applied in quantitative forest measurements were fitted to dominant height-age data and the best site index equation is : $SI=Exp^{(InHd-23.495(A^{-2}-0.04)}$. The site index curves constructed for the three sites (Omo Forest Reserve - OFR (J4), Oluwa Forest Reserve - OLFR and Shasha Forest Reserve - SFR) across the southwestern Nigeria using the chosen equation revealed that a 15 year old Pinus caribaea in the study area attained average dominant heights of 25, 22 and 21 m in OFR (J4), OLFR and SFR respectively. The site index equation and curves proffer veritable insight into better silvicultural options and management practices for the future plantations suitable sites.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.36-45
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• 1993

This paper presents a model and a heuristic procedure to design production planning and transportation scheduling systems of critical items, components and products on the basis of material requirement planning concept and transportation planning model. These systems are stemmed from a multi-site multi-product production company in a international economic zone. An example is provided to validate the heuristic procedure developed.

• Microbiology and Biotechnology Letters
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• v.26 no.5
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• pp.387-392
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• 1998

Brevibacterium lactofermentum, a gram-positive bacteria, has both the diaminopimelate (DAP) pathway and meso-DAP-dehydrogenase (DDH) pathway for L-lysine biosynthesis. To investigate importance of DDH pathway and the related ddh gene in lysine production, we introduced site-specific mutagenesis technique. A 300 bp DNA fragment central to the meso-DAP-dehydrogenase gene (ddh) of B. lactofermentum was used to inactive chromosomal ddh gene via homologous recombination. Southern hybridization analysis confirmed that the chromosomal ddh gene was disrupted by the vector sequence. The B. lactofementum ddh mutant obtained have an inactive DDH pathway. The results reveal that inactivation of the ddh gene in B. lactofermentum leads to dramatic reduction of lysine production as well as decrease of the growth rate, indicating that the DDH pathway is essential for high-level lysine production as well as biosynthesis of meso-DAP.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.263-270
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• 2017

The precast concrete (PC) structure has been preferred for reasons of shortening the construction time and securing the quality and, in particular, it has a cost saving effect in case of long span and heavy loaded structure with high floor height. Most engineers take it for granted to install the plant produced PC members. Researchers in several papers have argued that slander PC members such as columns and girders can be cost-effective if in-situ production is possible, while ensuring quality equal to or better than in-plant production. However, this argument is not officially accepted because objective verification has not been done. Therefore, the purpose of this study is to experimentally conduct in-situ production of PC members to verify the above claim. For this study, a storage building with long span and heavy loaded structure with high floor height was selected as a case study site. For the site, most of the PC members were supplied from the plant, and some of the columns were produced in the site for this study. As a result, it has been confirmed that it has a cost saving effect of 20% while having superior quality to plant-produced PC columns.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.11-12
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• 2011

The Construction Standard Production Unit(CSPU) has been used for the standard cost estimate in public and private construction projects. However, It is difficult to reflect the various site attributed variation in productivity using existing CSPU. The reason is that a criteria which site should be selection for enactment and/or revision of CSPU is not established. This study aims to provide essential data to be used for analyzing the labor factors in a way to secure efficiency and reliability of CSPU.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.96-106
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• 2021

The PC structure based on the OSC (Off-Site Construction) is mentioned as a representative method of innovation in the construction industry that converts the existing construction environment from site-centered to factory production-transportation-site assembly. However, recent research on PC method has focused on improving the functions of subsidiary materials and improving the production system to increase productivity and institutional / policy R&D that can be universally applied to the life-cycle stage of ordering / design /construction is insufficient. In particular, the absence of standardized cost calculation standards makes it difficult to calculate and verify of objectified appropriate construction cost. So which is an obstacle to the activation of the PC method. In this study, the standards for construction costs of domestic and foreign PC method were surveyed and similar Construction Standard Production Rates were analyzed to confirm the product structure suitable for PC method. Subsequently, the construction procedures and input resources for each PC subsidiary materials were identified through on-site surveys to derive component for subsidiary materials, and the factors of change in the product according to the construction characteristics(height, weight of subsidiary material) were verified. As a result the standard product calculation system suitable for the site installation of the PC method for apartment was presented.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1243-1244
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• 2022

In recent years, the growing interest in off-site construction has led to factories scaling up their manufacturing and production processes in the construction sector. Consequently, continuous large-scale site monitoring in low-variability environments, such as prefabricated components production plants (precast concrete production), has gained increasing importance. Although many studies on computer vision-based site monitoring have been conducted, challenges for deploying this technology for large-scale field applications still remain. One of the issues is collecting and transmitting vast amounts of video data. Continuous site monitoring systems are based on real-time video data collection and analysis, which requires excessive computational resources and network traffic. In addition, it is difficult to integrate various object information with different sizes and scales into a single scene. Various sizes and types of objects (e.g., workers, heavy equipment, and materials) exist in a plant production environment, and these objects should be detected simultaneously for effective site monitoring. However, with the existing object detection algorithms, it is difficult to simultaneously detect objects with significant differences in size because collecting and training massive amounts of object image data with various scales is necessary. This study thus developed a large-scale site monitoring system using edge computing and a small-object detection system to solve these problems. Edge computing is a distributed information technology architecture wherein the image or video data is processed near the originating source, not on a centralized server or cloud. By inferring information from the AI computing module equipped with CCTVs and communicating only the processed information with the server, it is possible to reduce excessive network traffic. Small-object detection is an innovative method to detect different-sized objects by cropping the raw image and setting the appropriate number of rows and columns for image splitting based on the target object size. This enables the detection of small objects from cropped and magnified images. The detected small objects can then be expressed in the original image. In the inference process, this study used the YOLO-v5 algorithm, known for its fast processing speed and widely used for real-time object detection. This method could effectively detect large and even small objects that were difficult to detect with the existing object detection algorithms. When the large-scale site monitoring system was tested, it performed well in detecting small objects, such as workers in a large-scale view of construction sites, which were inaccurately detected by the existing algorithms. Our next goal is to incorporate various safety monitoring and risk analysis algorithms into this system, such as collision risk estimation, based on the time-to-collision concept, enabling the optimization of safety routes by accumulating workers' paths and inferring the risky areas based on workers' trajectory patterns. Through such developments, this continuous large-scale site monitoring system can guide a construction plant's safety management system more effectively.

• Asian Journal of Atmospheric Environment
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• v.2 no.2
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• pp.116-124
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• 2008

In this study, the Tier 2 method recommended by the Intergovernmental Panel on Climate Change (IPCC) was used to predict the methane generation rate at two landfill sites, designated as Y and C for purposes of this study, in South Korea. Factors such as the average annual waste disposal, methane emissions ($L_0$) and methane gas generation rate constant (k) were estimated by analyses of waste and the historical data for the landfills. The value of k was estimated by field experiments and then the changes in the methane generation rate were predicted through the year 2050, based on the value of k. The Y landfill site, which was in operation until the year 2008, will generate a total of 17, 198.7 tons by the end of 2018, according to our estimations. At the C landfill site, which will not be closed until the end of 2011, the amount of methane gas generated in 2011 will be 3,316 tons and the total amount of gas generated by 2029 will be 61,200 tons. The total production rate of methane gas at the C landfill is higher than that of the Y landfill. This indicates that the capacity of a landfill site affects the production rate of methane gas. However, the interrelation between the generation rate of methane and the value of k is weak. In addition, the generation of methane gas does not cease even when the operations at a landfill site come to a close and the methane gas production rate is at its highest at end of the operating life of a landfill site.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.12
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• pp.1140-1145
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• 2008

In conventional cutting system of Heat-Shrink-Tube, workers operate cutting system after considering about length and quantity of heat-shrink-tube. So, not only work time and production cost is increased but also material is wasted because the data that workers have to consider is so much. In this paper, an effective cutting system of heat-shrink-tube was developed to reduce production cost, work time and waste of material. The cutting system consists of a supervisory computer installed inside a control room, a on-site computer installed on the work area, and a PLC system. In the developed system, a supervisory computer send work order to the on-site computer using LAN and the on-site computer operates the cutting system of the heatshrink-tube after it makes an array production order. Also, the on-site computer reports information to the supervisory computer when an accident happened.

• Journal of Ecology and Environment
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• v.38 no.3
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• pp.281-291
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• 2015

To clarify the effects of forest fire on the carbon budget of a forest ecosystem, this study compared the seasonal variation of soil respiration, net primary production and net ecosystem production (NEP) over the year in unburned and burned Pinus densiflora forest areas. The annual net carbon storage (i.e., NPP) was $5.75t\;C\;ha^{-1}$ in the unburned site and $2.14t\;C\;ha^{-1}$ in the burned site in 2012. The temperature sensitivity of soil respiration (i.e., $Q_{10}$ value) was higher in the unburned site than in the burned site. The annual soil respiration rate was estimated by the exponential regression equation with the soil temperatures continuously measured at the soil depth of 10 cm. The estimated annual soil respiration and heterotrophic respiration (HR) rates were 8.66 and $4.50t\;C\;ha^{-1}yr^{-1}$ in the unburned site and 4.08 and $2.12t\;C\;ha^{-1}yr^{-1}$ in the burned site, respectively. The estimated annual NEP in the unburned and burned forest areas was found to be 1.25 and $0.02t\;C\;ha^{-1}yr^{-1}$, respectively. Our results indicate that the differences of carbon budget and cycling between both study sites are considerably correlated with the losses of living plant biomass, insufficient nutrients and low organic materials in the forest soil due to severe damages caused by the forest fire. The burned Pinus densiflora forest area requires at least 50 years to attain the natural conditions of the forest ecosystem prior to the forest fire.