• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.102-103
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• 2014

Due to the nature of the existing load, the criteria of assessing the intensity of the lightweight wall's impact resistance has been though of as obscure. The current study, therefore, focuses on the standardized assessment of the impact resistance to the force of the large soft body applying to the lightweight wall. The gypsum board wall showed a low level of the maximum residual displacement. It is, however, required to be careful about the selection of the finishing process since the high level of the maximum displacement is likely to cause harm to finishing materials. Unlike the gypsum board, the ALC block wall displayed a considerable rigidity while showing almost no maximum residual displacement. Even with the low level of the maximum displacement due to the stiffness, the ALC block wall is still likely to be affected by the vibration derived from any impact on the surface, which demands a need for additional study. The future experimental study, accordingly, will focus on the impact of the vibration on finishing materials, consequently leading to the accurate prediction of the possibility of potential damage to the lightweight wall caused by the large soft body.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.69-79
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• 2017

The purpose of this study is to reconsider the rating method for the floor impact sound insulation performance in current criterion. Although there are some arguments about proper standard heavy impact source with reproducibility of actual impact source in residence building, bang machine is adopted as the only standard heavy impact source in domestic criterion. To inspect the rating methods of evaluation criteria, this study conducted vibration test for both of standard heavy impact sources and actual impact sources. Using the test results, the floor impact sound insulation performance levels were assessed by each of several criteria. In addition, low frequency noise beyond current criteria was evaluated. Consequently, the floor impact sound levels have different performance levels according to adopted criteria, and measured floor impact sounds are bound to annoy the neighbors in the low frequency range. Current criteria does not consider the spectrum characteristics of floor impact sound according to impact sources and low frequency noise. This may cause the difference between the floor impact sound insulation performance level and human perception. Thus current criterion needs to be complemented to reflect the spectrum characteristics of floor impact sound levels according to impact sources and sound pressure levels in low frequency range.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.563-569
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• 2020

Presenting the impact of meteorological disasters departs from the traditional weather forecasting approach for meteorological phenomena. It is important to provide impact forecasts so that precautions against disruption and damage can be taken. Countries such as the United States, the U.K., and France already conduct impact forecasting for heavy rain, heavy snow, and cold weather. This study improves and applies forecasts of the impact of heavy rain among various weather phenomena in accordance with domestic conditions. A total of 33 impact factors for heavy rain were constructed per 1 km grids, and four impact levels (minimal, minor, significant, and severe) were calculated using standard normal distribution. Estimated criteria were used as indicators to estimate heavy rain risk impacts for 6 categories (residential, commercial, utility, community, agriculture, and transport) centered on people, facilities, and traffic.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.7-9
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• 2014

An auditory experiment was conducted to establish annoyance criteria for floor impact noise in apartment buildings. Heavyweight floor impact sounds were recorded using an impact ball; the impact sound pressure level (SPL) together with the temporal decay rate (DR), which is quantified by the dB drop per second, was analyzed. For the experiment, A-weighted exposure levels of the heavy-weight floor impact sounds ranging 34~73 dB were evaluated at 3 dB intervals. Participants used a 7-point verbal scale to evaluate the level of annoyance from floor impact noise. The results show that the annoyance increases with increasing impact SPL and decreasing DR. Consequently, a classification and an acceptable level of floor impact sounds were proposed.

• Journal of Environmental Impact Assessment
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• v.13 no.3
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• pp.115-124
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• 2004

To utilize a closed municipal solid waste landfill site in environmentally secure conditions, it is necessary to verify the stabilization level of landfill leachate. To assess leachate stabilization of an open-dumping municipal solid waste landfill (Noeun Landfill) which is located at the upper drainage basin of Namhan River which flows into Lake Paldang utilized for Seoul Metropolitan water supplies, the surrounding characteristics of the landfill site was surveyed. After then, leachate, groundwater and soil samples from this landfill were chemically analyzed, and the analysis results were evaluated by "The Criteria of Landfill Waste Stabilization(CLWS)", "Discharge Criteria of Landfill Leachate", "The Criteria of Domestic Use in Groundwater Quality", and "Soil Contamination Criteria" promulgated by Korean Ministry of Environment. The closed open-dumping landfill was equipped with the final soil cover, 3 groundwater monitoring wells and poor landfill gas extraction devices for the post-closure management of the landfill. BOD/CODcr ratios in leachate were less than or slightly higher than 1/10. This results seemed to imply that the leachate stabilization level of this landfill based on the CLWS was almost completed. Qualities of groundwater sampled from monitoring wells located at outside of landfill were adequate for "The Criteria of Domestic Use in Groundwater Quality". Finally, concentrations of soil contaminants that were likely to be influenced by this landfill site were adequate to "Soil Contamination Criteria".

• Journal of KSNVE
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• v.7 no.2
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• pp.247-254
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• 1997

In the case of a precision equipment, it requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga class semiconductor wafers. This high technology equipments require very strict environmental vibration standard in proportion to the accuracy of the manufacturing, inspecting devices. The vibration criteria are usually obtained either by the real vibration exciting test on the equipment or by the analytical calculation. This paper proposes a new method to solve this problem at a time. The permissible vibration level to a precision equipment can be easily obtained by analyzing a process of Frequency Response Function. This paper also demonstrates its effectiveness by applying the proposed method to finding the vibration criteria of a Computer Hard Disk Driver by Impact Test.

• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.325-332
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• 2014

PURPOSE. The aim of this review was to analyze the evaluation criteria on mandibular implant overdentures through a systematic review and suggest standardized evaluation criteria. MATERIALS AND METHODS. A systematic literature search was conducted by PubMed search strategy and hand-searching of relevant journals from included studies considering inclusion and exclusion criteria. Randomized clinical trials (RCT) and clinical trial studies comparing attachment systems on mandibular implant overdentures until December, 2011 were selected. Twenty nine studies were finally selected and the data about evaluation methods were collected. RESULTS. Evaluation criteria could be classified into 4 groups (implant survival, peri-implant tissue evaluation, prosthetic evaluation, and patient satisfaction). Among 29 studies, 21 studies presented implant survival rate, while any studies reporting implant failure did not present cumulative implant survival rate. Seventeen studies evaluating peri-implant tissue status presented following items as evaluation criteria; marginal bone level (14), plaque Index (13), probing depth (8), bleeding index (8), attachment gingiva level (8), gingival index (6), amount of keratinized gingiva (1). Eighteen studies evaluating prosthetic maintenance and complication also presented following items as evaluation criteria; loose matrix (17), female detachment (15), denture fracture (15), denture relining (14), abutment fracture (14), abutment screw loosening (11), and occlusal adjustment (9). Atypical questionnaire (9), Visual analog scales (VAS) (4), and Oral Health Impact Profile (OHIP) (1) were used as the format of criteria to evaluate patients satisfaction in 14 studies. CONCLUSION. For evaluation of implant overdenture, it is necessary to include cumulative survival rate for implant evaluation. It is suggested that peri-implant tissue evaluation criteria include marginal bone level, plaque index, bleeding index, probing depth, and attached gingiva level. It is also suggested that prosthetic evaluation criteria include loose matrix, female detachment, denture fracture, denture relining, abutment fracture, abutment screw loosening, and occlusal adjustment. Finally standardized criteria like OHIP-EDENT or VAS are required for patient satisfaction.

• Journal of Distribution Science
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• v.12 no.12
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• pp.5-17
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• 2014

Purpose - The purpose of this study is to examine the possible ways to minimize damage by analyzing the influence that may be exerted upon the business process of the distribution industry by unexpected climate change. Research design, data, and methodology - The optimum business process is to be implemented after dividing the diversified business process of the distribution industry into the four stages of the Business Continuity Plan (BCP). Results - First, the upper-level risks that would be impacted most sensitively by climate change have been selected. Second, the impact and characteristics of the environment have been discovered. Third, weighted values by criteria item of upper-level business risks have been analyzed. Fourth, it was possible to define the business priority order based on the individual and then to adjust the Recovery Time Objective (RTO). Conclusion - In this study, the priority order has been defined quantitatively by calculating the priority order score. Further, the priority order has been determined depending on whether any targeted business unit is applicable to the items of the business nature criteria.

• Earthquakes and Structures
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• v.23 no.1
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• pp.87-100
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• 2022

Limiting the displacement of seismic isolators causes a pounding phenomenon under severe earthquakes. Therefore, the ASCE 7-16 has provided minimum criteria for the design of the isolated building. In this research the seismic response of isolated buildings by Triple Friction Pendulum Isolator (TFPI) under the impact, expected, and unexpected mass eccentricity was evaluated. Also, the effect of different design parameters on the seismic behavior of structural and nonstructural elements was found. For this, a special steel moment frame structure with a surrounding moat wall was designed according to the criteria, by considering different response modification coefficients (RI), and 20% mass eccentricity in one direction. Then, different values of these parameters and the damping of the base isolation were evaluated. The results show that the structural elements have acceptable behavior after impact, but the nonstructural components are placed in a moderate damage range after impact and the used improved methods could not ameliorate the level of damage. The reduction in the RI and the enhancement of the isolator's damping are beneficial up to a certain point for improving the seismic response after impact. The moat wall reduces torque and maximum absolute acceleration (MAA) due to unexpected enhancement of mass eccentricity. However, drifts of some stories increase. Also, the difference between the response of story drift by expected and unexpected mass eccentricity is less. This indicates that the minimum requirement displacement according to ASCE 7-16 criteria lead to acceptable results under the unexpected enhancement of mass eccentricity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.377-385
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• 1996

In the case of a precision equipment, it requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga class semiconductor wafers. This high technology equipments require very strict environmental vibration standard in proportion to the accuracy of the manufacturing, inspecting devices. The vibration criteria are usually obtained either by the real vibration exciting test on the equipment or by the analytical calculation. the former is accurate but requires a great deal of time and efforts while the latter lacks reliability. this paper proposes a new method to solve this problem at a time. the permissible vibration level to a precision equipment can be easily obtained by analyzing a process of Frequency Response Function. This paper also demonstrates its effectiveness by applying the proposed method to finding the vibration criteria of a Computer Hard Disk Drive by impact Test.