• Geomechanics and Engineering
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• v.35 no.2
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• pp.121-133
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• 2023

The demand for cement and limestone crushed materials has increased many folds due to the tremendous increase in construction activities in Pakistan during the past few decades. The number of cement production industries has increased correspondingly, and so the rock-blasting operations at the limestone quarry sites. However, the safety procedures warranted at these sites for the blast-induced ground vibrations (BIGV) have not been adequately developed and/or implemented. Proper prediction and monitoring of BIGV are necessary to ensure the safety of structures in the vicinity of these quarry sites. In this paper, an attempt has been made to predict BIGV using artificial neural network (ANN) at three selected limestone quarries of Pakistan. The ANN has been developed in Python using Keras with sequential model and dense layers. The hyper parameters and neurons in each of the activation layers has been optimized using randomized and grid search method. The input parameters for the model include distance, a maximum charge per delay (MCPD), depth of hole, burden, spacing, and number of blast holes, whereas, peak particle velocity (PPV) is taken as the only output parameter. A total of 110 blast vibrations datasets were recorded from three different limestone quarries. The dataset has been divided into 85% for neural network training, and 15% for testing of the network. A five-layer ANN is trained with Rectified Linear Unit (ReLU) activation function, Adam optimization algorithm with a learning rate of 0.001, and batch size of 32 with the topology of 6-32-32-256-1. The blast datasets were utilized to compare the performance of ANN, multivariate regression analysis (MVRA), and empirical predictors. The performance was evaluated using the coefficient of determination (R²), mean absolute error (MAE), mean squared error (MSE), mean absolute percentage error (MAPE), and root mean squared error (RMSE)for predicted and measured PPV. To determine the relative influence of each parameter on the PPV, sensitivity analyses were performed for all input parameters. The analyses reveal that ANN performs superior than MVRA and other empirical predictors, andthat83% PPV is affected by distance and MCPD while hole depth, number of blast holes, burden and spacing contribute for the remaining 17%. This research provides valuable insights into improving safety measures and ensuring the structural integrity of buildings near limestone quarry sites.

• Korean Journal of Construction Engineering and Management
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• v.25 no.3
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• pp.37-46
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• 2024

Recently, 3D laser scanning technology, which can collect accurate and quick information on phenomena, has been attracting attention among smart construction technologies. 3D laser scanning technology can obtain information most similar to reality at construction sites. In this study, we would like to apply a new member identification method to an actual building and present the possibility of applying point cloud data, which can be collected using 3D laser scanning technology, to measuring progress at construction sites. In order to carry out the research, we collected location information for component identification from BIM, set a recognition margin for the collected location information, and proceeded to identify the components that make up the building from point cloud data. Research results We confirmed that the columns, beams, walls, and slabs that make up a building can be identified from point cloud data. The identification results can be used to confirm all the parts that have been completed in the actual building, and can be used in conjunction with the unit price of each part in the project BOQ for prefabricated calculations. In addition, the point cloud data obtained through research can be used as accurate data for quality control monitoring of construction sites and building maintenance management. The research results can contribute to improving the timeliness and accuracy of construction information used in future project applications.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.675-687
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• 2005

The rocks of the five storied stone pagoda in the Jeongrimsaji temple site are 149 materials in total with porphyritic biotite granodiorite. They include pegmatite veinlet, basic xenolith and evenly developed plagioclase porphyry. This stone pagoda has comparably small fracture and cracks which are farmed in the times of rock properties, but surface exfoliation and granular decomposition are in process actively since the rocks are generally weakened from the influence of air contaminants and acid rain. Structural instability of constituting rocks in the 4th roof materials are observed to occur from distortion and tilt. Such instability is judged to threat stability of the upper part of the stone pagoda. Also, chemical weathering is operating even more as the contaminants, ferro-manganese hydroxides eluted from water-rock interaction on the rock surface. Most of the rock surface is covered with yellowish brown, dark black and light gray contaminants, and especially occur in the lower part of the roof rocks on each floor. The roof underpinning rocks are severe in surface pigmentation from manganese hydroxides and light gray contaminants. The surface of rocks lives bacteria. algae, lichen, or moss and diverse productions in colors of light gray, dark Bray and dark green. Grayish white crustose lichen grows thick on the surface with darkly discolored by fungi and algae in the first stage on basement rocks, and weeds grows wild on the upper part of each roof rocks. This stone pagoda must closely observe the movements of the upper part rock materials through minute safety diagnosis and long term monitoring for structural stability. Especially since the surface discoloration of rocks and pigmentation of secondary contaminants are severe, establishment of general restoration and scientific conservation treatment are necessary through more detailed study for this stone pagoda.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.94-105
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• 2009

Black locust (Robinia pseudoacacia) stand is representative lowland exotic plantation with low ecological quality and arrested succession in South Korea. To facilitate succession and restore natural vegetation, small canopy gaps (${\sim}57m^2$), which can modify minimally structural variables and reduce restoration related disturbances on stand, was established in the black locust stand, and oak (Quercus serrata) seedlings were introduced in the gap. Two types of varying levels were introduced for gap creation; cutting (C) and girdling (G) on canopies. Understory removal (CU and GU) treatment was applied as subtypes of structural modification. Growth (diameter, height and leaf area) of target species and responses (species composition, diversity and coverage) of understory community were monitored during study years (2007~2008). Canopy openness was different significantly among treatments but not for light availability. Based on the result of logistic regression, growth of height and leaf area of seedlings were significant variables on seedling survival. Height and leaf area of seedlings were increased during study years, although radial growth was reduced. During study years, there were no significant differences in species composition and diversity, and total coverage increased about 20%. Increase of resources by gap creation and understory removal likely affect growth of target species. Small gap creation was effective to reduce understory responses in composition and diverstiy. Synthesized, growth of target species and responses of understory community to small canopy gap creation exhibited, in short term, possibility of utilization in alternative forest restoration and management option. Long-term monitoring is necessary to certificate effect of artificial gap creation on forest restoration.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.79-86
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• 2009

In a steel structure, spray-applied fire resistive materials are crucial in preventing structural strength from being weakened in the event of a fire. The quality control of such materials, however, is difficult for manual workers, who can frequently be in short supply. These skilled workers are also very likely to be exposed to environmental hazards. Problems with construction work such as this, which are specifically the difficulty of achieving quality control and the dangerous nature of the work itself, can be solved to some degree by the introduction of automated equipment. It is, however, very difficult to automate the work process, from operation to the selection of a location for the equipment, as the environment of a construction site has not yet been structured to accommodate automation. This is a fundamental study on the possibility of the automation of spray-applied fire resistive coating work. In this study, the linkability of the cutting-edge RTLS to an automation system is reviewed, and a scenario for the automation of spray-applied fire resistive coating work and system composition is presented. The system suggested in this study is still in a conceptual stage, and as such, there are many restrictions still to be resolved. Despite this fact, automation is expected to have good effectiveness in terms of preventing fire from spreading by maintaining a certain level of strength at a high temperature when a fire occurs, as it maintains the thickness of the fire-resistive coating at a specified level, and secures the integrity of the coating with the steel structure, thereby enhancing the fire-resistive performance. It also expected that if future research is conducted in this area in relation to a cutting-edge monitoring TRS, such as the ubiquitous sensor network (USN) and/or building information model (BIM), it will contribute to raising the level of construction automation in Korea, reducing costs through the systematic and efficient management of construction resources, shortening construction periods, and implementing more precise construction

• Food Science of Animal Resources
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• v.27 no.1
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• pp.117-121
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• 2007

The number of internet users and the scale of electronic on-line trading are on the increase due to the development of information technology and the internet. The aim of this study was to monitor the accuracy of country-of-origin labels and the indicated contents of meat available by electronic on-line trading by using a structural interview sheet for 100 on-line meat product markets. The result of this investigation showed a 100% level of accuracy for business name and telephone number whereas the company address, meat manufacturer and supplier, and business registration were less reliable. We also investigated the accuracy of site policy, e-mail address, and fax number. The results showed that the accuracy of fax numbers was the lowest. The product name and the kind of meat actually in the product showed a 100% level of conformity, while the price (96.3%), place of origin (93.6%), capacity (90.4%), meat parts (80.9%) and contents of the product (73.4%) showed a relatively low level of conformity. Serious safety issues were exposed by the disturbingly low 20.2% accuracy of indicated expiration dates and 5.3% accuracy of indicated manufacturing dates. To ensure food safety, it is essential to improve consumer understanding and trust regarding food safety through continuous public relations. More education and information are needed to raise consumer awareness of the facts versus myths regarding food safety.

• Journal of the Korean Society of Child Welfare
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• no.56
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• pp.133-164
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• 2016

This study investigated the effect of housing poverty in childhood on adolescents' subjective well-being. Specifically, this study examined whether the major factors that have been known to affect adolescents' well-being (i.e., family relationships, peer relationships, school adjustment etc.) mediated the relationship between housing poverty and adolescents' well-being. And then this study aimed to present an empirical evidence for establishing policies against housing poverty in order to enhance adolescent's subjective happiness. Data were derived from the $1^{st}$, $4^{th}$, and $7^{th}$ surveys of the Korea Welfare Panel Study(KOWEPS), and the sample included. 512 high school children in the $7^{th}$ survey. This study utilized structural equation modeling. Housing poverty was measured by the sub-minimum standard housing condition and the household's burden of housing expenditure. Family relationship, as a mediator, was measured by parental involvement in education, parental monitoring, and family conflicts. Another mediator, school adjustment was measured by school environment and school bonding, and the last mediator, peer relationship was measured by friend attachment and peer attachment. The results showed that housing poverty had significant negative effects on the adolescents' subjective well-being. The sub-minimum standard housing condition with inadequate size and facilities negatively affected adolescents' relationships with family directly and subjective well-being indirectly. In addition, the negative family relationships due to the sub-minimum standard housing condition negatively affected adolescents' subjective well-being through school adjustment and peer relationships. The greater the proportion of income a household spends on housing expenditure, the less likely for adolescents to report positive well-being. The sub-minimum standard housing condition had indirect effects through family relationships, whereas the household's housing expenditure directly affected adolescents' subjective well-being. This study suggested the necessity of interventions to alleviate housing poverty for adolescents' families and lays the groundwork for housing poverty policies in Korea.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.287-294
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• 2021

In order to expand facility agriculture and reduce greenhouse construction costs in reclaimed land, a greenhouse foundation method that satisfies economic feasibility and structural safety at the same time is required. As an alternative, the allowable bearing capacity and settlement were reviewed when the DCM(Deep cement mixing) method was applied among the soft ground reinforcement methods. To examine the applicability of the greenhouse foundation, the allowable bearing capacity and settlement were calculated by applying the theory of Terzaghi, Meyerhof, Hansen, and Schmertmann. In case of the diameter of 800mm and the width and length of the foundation of 4m, the allowable bearing capacity was 179kN/m² and the settlement was 7.25mm, which satisfies the required bearing capacity and settlement standards. The calculation results were verified through FEM(Finite element method) analysis using the Mohr-Coulomb material model. The allowable bearing capacity was 169kN/m² and the settlement was 2.52mm. The bearing capacity showed an error of 5.6% compared to calculated value, and the settlement showed and error of 65.4%. Through theoretical calculations and FEM analysis, it was confirmed that the allowable bearing capacity and settlement satisfies the design criteria as a greenhouse foundation when the width and length of the foundation were 4m. Based on the verified design values, it is expected to be able to present the foundation design criteria for greenhouses through empirical tests such as bearing capacity tests and long-term settlement monitoring.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.4
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• pp.316-333
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• 2021

In order to understand basic data for improving the fishing system and fishing vessel structure in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 to analyze opinions on the improvement of operation status and fishing vessel structure. The questionnaire survey consisted of ten questions on the operation status of coastal improved stow net fishery and six questions on the improvement of fishing vessel structure, and the results of each question were analyzed by the region, the captain's age, the captain's career and the age of fishing vessel. As a result of analyzing opinions on the operation status of the coastal improved stow net fishery, it was found that the average time required for casting net was 32.8 to 33.0 minutes and that the average time required for hauling net was 41.0 to 42.2 minutes which took 10 to 12 minutes more than for casting net. The most important work requiring improvement during fishing operation (the first priority) were 'hauling net operation,' 'readjustment and storage of fishing gear,' and 'fish handling' and the hardest factor in fishing management were in the order of 'reduction of catch,' 'labor shortage' and 'rising labor costs.' The most institutional improvement that is most needed in coastal improved stow net fishery was an 'using fine mesh nets.' Most of the respondent to the questions on the experience in hiring foreign crews was 'either hiring or willing to hire foreign crews,' and the average number of foreign crews employed was found to be 2.3 to 2.4 persons. The most important reason for hiring (or considering employment) foreign crews was 'high labor costs.' The degree of communication with foreign crews during fishing operation were 'moderate' or 'difficult to direct work.' The most important problem in hiring foreign crews (the first priority) was an 'illegal departure.' As the survey results on the opinion of structural improvement of coastal improved stow net fishing vessel, the degree of satisfaction with fishing vessel structure related to fishing operation was found to be somewhat unsatisfactory, with an average of 3.3 points on a five-point scale. The inconvenient structure of fishing vessel in possession (the first priority), the space needed most for the construction of new fishing vessel (the first priority) and the space considered important for the construction of new fishing vessel (the first prioprity) was a 'fish warehouse.' The most preferred equipment for the construction of new fishing vessel were 'engine operation monitoring' and 'navigation safety devices.' The average size (tonnage class), the average horse power and the average total length of fishing vessel for proper profit and safety fishing operation was between 13.8 and 14.0 tonnes, 808.3 to 819.5 H.P. and 23.4 to 23.5 meters, respectively. The results of the operation status of coastal improved stow net fishery and the requirement for improving the fishing vessel structure are expected to be provided as basic data for reference when we build or improve the fishing vessel.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3A
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• pp.297-307
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• 2010

Recently, maintenance engineering and technology for civil and building structures have begun to draw big attention and actually the number of structures that need to be evaluate on structural safety due to deterioration and performance degradation of structures are rapidly increasing. When stiffness is decreased because of deterioration of structures and member cracks, dynamic characteristics of structures would be changed. And it is important that the damaged areas and extent of the damage are correctly evaluated by analyzing dynamic characteristics from the actual behavior of a structure. In general, typical measurement instruments used for structure monitoring are dynamic instruments. Existing dynamic instruments are not easy to obtain reliable data when the cable connecting measurement sensors and device is long, and have uneconomical for 1 to 1 connection process between each sensor and instrument. Therefore, a method without attaching sensors to measure vibration at a long range is required. The representative applicable non-contact methods to measure the vibration of structures are laser doppler effect, a method using GPS, and image processing technique. The method using laser doppler effect shows relatively high accuracy but uneconomical while the method using GPS requires expensive equipment, and has its signal's own error and limited speed of sampling rate. But the method using image signal is simple and economical, and is proper to get vibration of inaccessible structures and dynamic characteristics. Image signals of camera instead of sensors had been recently used by many researchers. But the existing method, which records a point of a target attached on a structure and then measures vibration using image processing technique, could have relatively the limited objects of measurement. Therefore, this study conducted shaking table test and field load test to verify the validity of the method that can measure multi-point displacement responses of structures using image processing technique.