• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6C
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• pp.367-377
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• 2008

As part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the framework of reliability theory. The 57 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and these load test piles were sorted into two cases: SPT N at pile tip less than 50, SPT N at pile tip equal to or more than 50. The static bearing capacity formula and the Meyerhof method using N values were applied to calculate the expected design bearing capacities of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative measured bearing capacities with the expected design values. Reliability analysis was performed by two types of advanced methods: the First Order Reliability Method (FORM), and the Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, in consideration of the reliability level of the current design practice, redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure. Resistance factors of driven steel pipe piles were recommended based on the results derived from the First Order Reliability Method and the Monte Carlo Simulation method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1C
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• pp.19-29
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• 2008

As a part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, reliability analyses for driven steel pipe piles are performed and the target reliability indices are selected carefully. The 58 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles. The static bearing capacity formula and the Meyerhof method using N values are applied to calculate the expected design bearing capacity of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative bearing capacities with the design values. Reliability analysis was performed by two types of advanced methods: First Order Reliability Method (FORM), and Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The static bearing capacity formula exhibited relatively small variation, whereas the Meyerhof method showed relatively high inherent conservatism in the resistance bias factors. Reliability indices for safety factors in the range of 3 to 5 were evaluated respectively as 1.50~2.89 and 1.61~2.72 for both of the static bearing capacity formula and the Meyerhof method. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, based on the reliability level of the current design practice and considering redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.1013-1022
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• 2006

Although the cable-stayed bridges with two I-type girders inherently do not have good aerodynamic characteristics, a lot of the bridges with this type girders are constructed in Korea recently because of an economical merit. This paper investigated the aerodynamic characteristics of the cable-stayed bridges with two I-type girders. Section model tests were conducted in order to investigate the aerodynamic behaviors of this section with varying of the angles of attack, turbulence intensity and damping ratios. Two deck section configurations with different torsional stiffness were studied under construction and after completion respectively. Three types of the fairings were investigated to improve the aerodynamic characteristics of the bridges. The result of this study showed that the traditional section model test in uniform flow estimates the aerodynamic behavior rather pessimistically. The wind induced responses of the bridges were severely varied in accordance with the turbulence intensity and the structural damping ratio. The proposed fairing reduced the magnitude of the vortex-shedding vibrations and buffeting responses. It also increased the wind speed at which flutter occurs. It is expected that these investigations would provide a lot of information for the design of the cable stayed bridges with two I-type girders regarding wind resistance.

• Smart Media Journal
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• v.12 no.5
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• pp.36-45
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• 2023

Recently, in digital agriculture, the types and utilization of greenhouses based on IoT are spreading, and greenhouses are being modernized, enlarged, and even factoryized using smart technology. However, a specific standardization plan has not been proposed according to the equipment for data collection in the smart greenhouse and the size or shape of the greenhouse. In other words, there is a lack of standard data for facility equipment, such as the type and number of sensors and equipment according to the size of the greenhouse, the type of greenhouse construction film and materials suitable for crops and carbon neutrality. Therefore, in this study, the suitability of the implementation, installation and quantity of IoT equipment for data collection was tested, and some standard technologies were presented through the implementation of data collection and communication methods. In addition, impact strength, tensile, tear, elongation, light transmittance, and lifespan issues for PE, PVC, and EVA, which account for about 90% of existing greenhouses, were presented, and the shape, size, and environmental problems of greenhouses made of films were presented. presented in the text. In this research paper, a standardized carbon-neutral modular smart greenhouse using nano-material film was implemented as a solution to environmental problems such as greenhouse size, farm crop type, greenhouse lifespan, and film, and its performance with existing greenhouses was analyzed and presented. Through this, we propose a modularized greenhouse that can be expanded or reduced freely without distinction in the size of the greenhouse or the shape of farmhouse crops, and the lifespan is extended and standardized. Finally, the average characteristics of greenhouses using existing PE, PVC, and EVA films and the characteristics of greenhouses using new carbon-neutral nanomaterials are compared and reviewed, and a plan to implement an expandable IoT greenhouse that supports carbon neutrality is proposed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.199-211
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• 2009

Development of underground space is actively performed globally for better life in the surface, and the scale of the space is increasing. Extreme care should be taken in the construction of the underground space in urban areas in order to avoid damage of adjacent structures and interference with existing underground space. In case of shallow tunnels, reinforcement of ground and structures is necessary to minimize the damage to structures due to excavation but any standard for optimum range of the reinforcement has not been established yet. In this paper, a series of numerical analyses have been performed for a 20 m diameter tunnel excavated underneath a structure to investigate the degree of damage of the structure according to vertical and horizontal spacing between the tunnel and structure. In addition to that, optimum range of reinforcement is presented for each case where reinforcement is required. It has been observed that the reinforcement is necessary for the ground condition adapted in the analyses as follows: (1) if horizontal spacing ($S_{H}$) approaches to 0D (D: equivalent diameter of tunnel) for vertical spacing (Sv) of 0.5D, and (2) if tunnel exists underneath the structure for vertical spacing (Sv) of 0.75D. The reinforcement is not necessary for Sv of 10 regardless of $S_{H}$. It also has been obtained that the optimum ranges of the reinforcement around structure foundation are 7 m in depth and whole width of the structure and 5 m beyond tunnel sidewall. These reinforcememt ranges have been confirmed to be enough for stability of the structure if types of reinforcement method is appropriately selected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.212-215
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• 2022

In the era of so-called digital transformation today, the need for the construction and utilization of big data in various fields has increased. Today, a lot of data is produced and stored in a digital device and media-friendly manner, but the production and storage of data for a long time in the past has been dominated by print books. Therefore, the need for Optical Character Recognition (OCR) technology to utilize the vast amount of print books accumulated for a long time as big data was also required in line with the need for big data. In this study, a system for digitizing the structure and content of a document object inside a scanned book image is proposed. The proposal system largely consists of the following three steps. 1) Recognition of area information by document objects (table, equation, picture, text body) in scanned book image. 2) OCR processing for each area of the text body-table-formula module according to recognized document object areas. 3) The processed document informations gather up and returned to the JSON format. The model proposed in this study uses an open-source project that additional learning and improvement. Intelligent OCR proposed as a system in this study showed commercial OCR software-level performance in processing four types of document objects(table, equation, image, text body).

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.318-318
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• 2022

Basil(Ocimum basilicum L.) is an annual herb that grows wild in hot and humid regions such as tropical Asia and Africa. This study was carried out for resource discovery, propagation, and DB construction of aromatic plants. In order to evaluate the genetic characteristics, 28 kinds of basil seeds were supplied from the Center for Genetic Resources. For basil characteristics, planting date, plant height, growth shape, leaf length, leaf shape, petiole color, petiole, stem color, flower color, after harvest, Ml length including roots, flower length, stem thickness and biological weight were measured. For anthocyanin analysis, only basil with purple color was selected, anthocyanins were extracted with 60% ethanol containing 1% citric acid, a standard quantitative curve was prepared with cyanidin-3-glucoside, and absorbance was measured at 525 nm. Basil planting started around June 16, and the flowering period lasted for a total of 18 days from July 19 to August 5. On August 6, when flowering was completed, morphological characteristics including flower color were measured at the site by an object. The measured basil plant length was 26.6-59.6 cm, leaf length 2.0-7.9 cm, leaf width 0.7-5.2 cm, and petiole 1.3-3.9 cm. The growth pattern of basil was generally straight, medium in shape. The color of the leaves was observed evenly by mixed green, purple, purple and green, and the recesses in the shape of the leaf were also conspicuously observed. A total of three basil flower colors were observed: white, light pink(149P 10P/84), and purple(37V 2.5RP 4/12). During the second growth survey after harvest, the total length including the basil roots is 26.7-52.0 cm, the flower length is 8.2-29.3cm, the stem thickness is 7.1-15.9mm, the number of stem nodes is 3-12 nodes, and the total weight of the basil was measured to be about 218-1540 g. There are a total of 16 types of basil expressed in purple, and the anthocyanin content was measured to be 73.74 ~ 380.72 mg/100g.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.3
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• pp.337-357
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• 2023

Universities and local governments in Korea are simultaneously experiencing the difficulties of a decrease in the youth population and a decrease in the school-age population, and close cooperation between universities and local governments is urgently needed to solve this problem. Representative methods of such cooperation include the establishment of a regional innovation system and the theories of innovation clusters and triple helix models. In addition to these theories, the aim is to derive sustainable conditions for the local government-university cooperation model by examining various cases of cooperation at home and abroad. This is the purpose of this paper. In particular, through case studies of cooperation between local governments and universities at home and abroad, three types of models (job, education, and housing) were analyzed, and common conditions and requirements for sustainable cooperation were proposed. In order for cooperation between local governments and universities to continue and produce successful results, mutual benefit creation, infrastructure construction and operation appropriate for capabilities, flexibility, and mutual responsibility are necessary. Furthermore, a model that suits the capabilities of local governments and universities must be found, and in this process, the university's research capabilities and commercialization capabilities of research results are especially important. In addition, it is essential to establish a new cooperation system between local governments, universities, and the central government.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.572-583
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• 2023

Demand for wood in construction is increasing worldwide. In Korea, technical reviews of high-rise Cross Laminated Timber (CLT) buildings are under way. In this paper, Floor Impact Sound Insulation Performance (FISIP) and Transmission Loss (TL) of 150 mm thick CLT floor panels made of two domestic species, Larix kaempferi and Pinus densiflora, are investigated. The CLT slabs were tested in reverberation chambers connected vertically. When comparing Single Number Quantity (SNQ) of FISIP of the bare panels, the Larix CLT is 3 dB lower in heavy-weight and 1 dB in light-weight than the Pinus CLT. However, there was no difference when concrete toppings were added to improve the performance. As the concrete toppings became thicker, the heavy-weight was reduced by 9 dB ~ 20 dB, and the light-weight by 20 dB ~ 30 dB. And the analysis of these results with area density has confirmed that the area densities are highly correlated (R² = 0.94 ~ 0.99) to the FISIP of the CLT. The types of CLT didn't affect the TL. Comparison of theoretical TL values with measured TL values has shown that the frequency characteristics are similar but 8 dB ~ 12 dB lower in measured values. The relationship between the TL and frequency characteristics of the tested CLT slabs was derived by using the correction value.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.233-257
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• 2023

Asbestos minerals are found at rocks and soils of the Hongseong and Bibong serpentine mines, western part of Chungnam. The area consists of and metasediment, and Mesozoic igneous intrusives with minor age-known gneiss complexes and Mesozoic sediments. With detailed geological investigations, rock samples for the serpentinite and amphibolite areas are collected at sites containing asbestos. Representative asbestos and rock samples are analysed by PLM, XRD, SEM and EPMA. Serpentinites are found as steeply dipping faults with adjacent gneiss complex to the NNE direction. Repeated alteration, including serpenitization and talcification, is found at the emplacement direction for the serpentinite body. Amphibollites occur as intrusives and stratiforms within the Precambrian gneiss complex. Serpentinite and amphibolite (or amphibole schist) contain amphiboles either as asbestiform or non-asbestiform. Varying amounts of asbestos minerals, including chrysotile, tremolite asbestos and actinolite asbestos, are found within the serpentinites. The asbestos minerals are found near the cracks or fractures and along the bedding plane. They occur as cross fiber, slip fiber and mass fiber types. Varying amounts of amphibole asbestos minerals, such as tremolite and actinolite asbestos, are found within amphibolites and as a mass fiber type. Overall results suggest that rocks of the serpentine mines contain serpentine and amphibole type asbestos minerals originated from the hydrothermal alteration. Considering construction nearby the mines and environmental risks by the asbestos, additional land management plans are required.