• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.61-65
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• 2010

Most of the chemical reactions performed in the chemical industry are exothermic, meaning that thermal energy is released during the reaction. It is also important to understand the thermal hazards such as thermal stabilities and runaway reactions, which are governed by thermodynamics and reaction kinetics of the mixed materials. The paper was described the evaluation of thermal behavior caused by an exothermic batch process in manufacture of the vinyl acetate resin. The aim of the study was to evaluate the thermal stabilities of raw materials with operating conditions such as a reaction inhibitor, heating rate, reaction atmosphere and the mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed in the differential scanning calorimeter(DSC), C 80 calorimeter, and thermal screening unit($TS^u$). It was suggested that we should provide the thermal characteristics for raw materials to present safe precautions with operating conditions in the vinyl acetate polymerization process.

• Smart Structures and Systems
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• v.11 no.1
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• pp.35-51
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• 2013

Over the last two decades Wavelet Transformation (WT) method has been widely utilized for the damage identification of structures. The main objective of this paper is to discuss and present some of common shortcomings and limitations of mathematical software, as well as other precautionary measures that need to be considered when using them for wavelet analysis applications. Due to popular usage of MATLABMATLAB(R) comparing to other mathematical tools among researchers for data processing of structural responses through WT analysis, this software was chosen for specific study. To the best of the authors' knowledge, these limitations and observations have not been previously identified or discussed in the literature. In this work, a square plate with a severe damage, in form of a crack, parallel to the left edge of the plate is selected for a pilot study. The steady state harmonic response is used for measuring the deflection shape across the line parallel to one edge and perpendicular to the damage. Several criteria and cases such as the smallest size damage that can be detected, correlation between the crack width and the number of sampling points, and the influence of the damage thickness on the accuracy of the result are investigated.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1227-1236
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• 2018

From all of the environmental problems, blast-induced vibrations often cause concern to surrounding residents. It is often claimed that damage to building superstructures is due to blasting, and sometimes the building owner files a lawsuit against the company that perform blasting operations. The blast-vibration problem has been thoroughly investigated in the past and continues to be the subject of ongoing research. In this study, a tunnel construction has been performed by a construction company, according to their contract they must have used drilling & blasting method for excavation in tunnel inlet and outlet portal. The population is very condensed with almost tunnel below in the vicinity houses of one or two floors, typically built with stone masonry and concrete. This situation forces the company to take extreme precautions when they are designing blasts so that the blast effects, which are mainly vibration and aerial waves, do not disturb their surrounding neighbors. For this purpose, the vibration measurement and analysis have been carried out and a new methodology in minimizing the blast induced ground vibrations at the target location, was also applied. Peak particle velocity and dominant frequencies were taken into consideration in analyzing the blast-induced ground vibration. The methodology aims to employ the most suitable time delays among blast-hole groupings to render destructive interference of surface waves at the target location.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.803-817
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• 2017

Structural health monitoring has increasingly been a focus within the civil engineering research community over the last few decades. With increasing application of sensor networks in large structures and infrastructure systems, effective use and development of robust algorithms to analyze large volumes of data and to extract the desired features has become a challenging problem. In this paper, we grasp some precautions and key points of the signal processing approach, wavelet, establish a relative reliable framework, and analyze three problems that require attention when applying wavelet based damage detection approach. The cases studies how to use optimal scales for extracting mode shapes and modal curvatures in a reinforced concrete beam and how to effectively identify damages using maximum curves of wavelet coefficient differences. Moreover, how to make a recognition based on the wavelet multi-resolution analysis, wavelet packet energy, and fuzzy sets is a meaningful topic that has been addressed in this work. The relative systematic work that compasses algorithms, structures and evaluation paves a way to a framework regarding effective structural health monitoring, orientation, decision and action.

• The Korean Journal of Pain
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• v.23 no.1
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• pp.24-27
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• 2010

Background: Fluoroscopy has been an integral part of modern interventional pain management. Yet fluoroscopy can be associated with risks for the patients and clinicians unless it is managed with appropriate understanding, skill and vigilance. Therefore, this study was designed to determine the amount of radiation received by a primary operator and an assistant during interventional pain procedures that involve the use of fluoroscopy. Methods: In order to examine the amount of radiation, the physicians were monitored by having them wear three thermoluminescent badges during each single procedure, with one under a lead apron, one under the apron collar and one on the leg during each single procedure. The data obtained from each thermoluminescent badge was reviewed from September 2008 to November 2008 and the annual radiation exposure was subsequently calculated. Results: A total of 505 interventional procedures were performed with C-arm fluoroscopy during three months. The results of this study revealed that the annual radiation exposure was relatively low for both the operator and assistant. Conclusions: With proper precautions, the use of fluoroscopy during interventional pain procedures is a safe practice.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.23.1-23.10
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• 2019

The choice of surgical technique in orthognathic surgery is based primarily on the surgical treatment objectives (STO), which is a fundamental component of the orthognathic treatment process. In the conventional orthodontics-first approach, presurgical planning can be performed twice, during the preorthodontic (initial STO) and presurgical phases (final STO). Recently, a surgery-first orthognathic approach (SFA) without presurgical orthodontic treatment has been introduced and combined initial and final STO at the same time. In contrast to the conventional surgical-orthodontic treatment protocol that includes preoperative orthodontics for dental decompensations to maximize stable postoperative occlusion, the SFA potentially shortens the treatment period and minimizes esthetic concerns during the decompensation period because skeletal problems are corrected from the beginning. The indications for the SFA have been proposed in the literature, but no consensus exists. Moreover, because dental occlusion of the pre-orthodontic arches cannot be used as a guide for establishing the surgical treatment plan, there are fundamental limitations in accurate prediction of postsurgical results in the SFA. Recently, the concepts of postsurgical orthodontic treatment are continuously changing and evolving to overcome this inherent limitation of the SFA. The elimination of presurgical orthodontics can change the paradigm of orthognathic surgery but still requires cautious case selection and thorough discussion and collaboration between orthodontists and surgeons regarding the goals and postoperative management of the orthognathic procedure.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.1
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• pp.39-44
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• 2020

Homozygous familial hypercholesterolemia (HoFH) is a rare inherited disorder that presents as abnormally elevated levels of low-density lipoprotein cholesterol and premature heart disease, requiring frequent intervention through lipid apheresis for management. The risk of perioperative cardiac events is higher in patients with HoFH because of its pathophysiological manifestations in the vascular system. Careful cardiac precautions and anesthetic assessments are necessary to ensure patient safety. In the following case report, we discuss the clinical course and anesthetic considerations for a 14-year-old girl with HoFH undergoing sedation for dental extractions and mandibular molar uprighting in an outpatient oral surgery clinic. Considerations included the use of heparin in the patient's weekly plasma lipid apheresis treatment. In order to reduce the risks of peri- and postoperative bleeding and perioperative cardiac events, the operation was scheduled for 4 days after apheresis. This allowed for adequate heparin clearance, while also reducing the likelihood of possible cardiac events. A literature review revealed no results for the outpatient management of patients with HoFH undergoing sedation for noncardiac procedures. Our reported case serves as a clinical example for physicians to be utilized in the future.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.206-208
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• 2013

The fact that the gigantic and luxurious cruise, Titanic, sank into the cold winter sea causing 1,490 casualties in 1912 resulted in discussing safety of life at sea international and Korea has adopted and operated the GMDSS to keep up with those international endeavors to decrease the number of tragic accidents at sea, However, all GMDSS equipment is making a monotonous beep sound when receiving a distress, emergency, safety and even general message so that it might contribute to lowering ship operators' cognitive abilities as well as being dull of safety precautions. So, I'd like to render great services for saving even one person by considering developing an automatic audio alarm device which allows people to respond in a prompt manner as soon as they hear an audion alarm such as a shipwreck.

• The Journal of the Korean dental association
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• v.49 no.11
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• pp.670-678
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• 2011

Various sorts of dental devices for the dental treatment have been introduced and adopted during past several years. Dental Laser, among all devices, seems to be possible for applying to over the whole treatments and widely employed. Furthermore, this article is to introduce that Dental Laser is intended to care patients secured with the effectual treatment against Conventional procedures based upon its studies. The advantages of Dental Laser treatment-along with LLLT (Low Level Laser Therapy) effect, biostimulation effect, and minimal invasive technique - make the patients reduce their fear of the operation, lighten the inconvenience of post operation, and shorten the treatment period. In particular, it is worth considering that the use of laser-assisted therapies is associated with a marked reduction in the use of analgesics and anti-inflammatory medications compared with conventional procedures. This article is to state advantages and differences of Dental Laser treatment compared with Conventional procedures, and to emphasize to become well-acquainted with the precautions for safety and effective Dental Laser treatment. In case of operating Dental Laser with lack of the instructions, it will cause the unpredicted fatal results; therefore this treatment requires special care in its operation. Henceforward, it is anticipated that infinite treatment protocols will be introduced by applying Dental Laser, and this is to address the utilization of Dental Laser.

• Journal of the Korean Society of Marine Environment & Safety
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• v.9 no.1
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• pp.17-23
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• 2003

With the terrorist attacks on 11 September 2001, the ships and their crew' safety and security have become a major issue in the maritime industries, In high-risk terrorism, not only ship owners and port authorities but also crew members on board should take precautions in the conduct of their business. In this paper, the vulnerability and essential elements in overall security of merchant ship are analyzed with a discussion in depth of the concept and principles of maritime security of merchant ship are analyzed with a discussion in depth of the concept and principles of maritime security management. And then, ship's security model and security system to reduce security rish and to minimize damage are proposed.