• Earthquakes and Structures
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• 제22권2호
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• pp.109-120
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• 2022

Older or damaged structures can require significant retrofit to ensure they perform well in subsequent earthquakes. Supplemental damping devices are used to achieve this goal, but increase base shear forces, foundation demand, and cost. Displacement reduction without increasing base shear is possible using novel semi-active and recently-created passive devices, which offer energy dissipation in selected quadrants of the force-displacement response. Combining these devices with large, strictly passive energy dissipation devices can offer greater, yet customized response reductions. Supplemental damping to reduce response without increasing base shear enables a net-zero base shear approach. This study evaluates this concept using two incremental dynamic analyses (IDAs) to show displacement reductions up to 40% without increasing base shear, more than would be achieved for either device alone, significantly reducing the risk of response exceeding the unaltered structural case. IDA results lead to direct calculation of reductions in risk and annualized economic cost for adding these devices using this net-zero concept, thus quantifying the trade-off. The overall device assessment and risk analysis method presented provides a generalizable proof-of-concept approach, and provides a framework for assessing the impact and economic cost-benefit of using modern supplemental energy dissipation devices.

• 대한두개안면성형외과학회지
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• 제10권1호
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• pp.33-36
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• 2009

Purpose: Fractures of the mandibular condylar area are common injuries that account for 29% to 40% of fractures of the facial bones and represent 20% to 62% of all mandibular fractures. Currently 3 main methods are being used in the treatment of mandibular subcondylar fractures: closed reduction; open reduction and internal fixation; Endoscopic reduction and internal fixation. Each method has its proponents and opponent as well as advantages and disadvantages, and indications for each vary among surgeons. There are six approaches of open reduction: submandibular, retromandibular, preaurilcular, postauricular, intraoral, transparotid approach. Among them, transparotid approach has been described for subcondylar exposure with dissection in the direction of facial nerve fibers to expose the bone through the parotid gland. This approach carries the risk of a parotid glandular fistula as well as facial nerve injury but has the advantage of being directly over the fracture site. We report safety and efficacy of surgical treatment using a transparotid approach for direct plating. Methods: A 43-year-old man sustained multiple facial bone fractures by driver traffic accident. Mandibular subcondyle was fractured and dislocated internally. We performed open reduction and internal fixation by transparotid approach. Fractured site was fixed by titanium mini plate & screw. We applicated arch bar for approximately 3 weeks. Results: Follow-up length was about 5months. Scar of surgical incision was indistinct, there was no symptoms and signs of facial nerve and parotid gland injury, and maximal mouth opening was measured 49.5 mm. Conclusion: Transparotid approach has high risks of facial nerve and parotid gland injury, but paradoxically it is the most effective technique in saving facial nerve. Open reduction and internal fixation of mandibular subcondylar fracture by transparotid approach with precise and versed procedure, best outcome can be expected.

• Structural Engineering and Mechanics
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• 제63권1호
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• pp.47-53
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• 2017

The fundamental goal of this study is to minimize the uncertainty of the median fragility curve and to assess the structural vulnerability under earthquake excitation. Bayesian Inference with Markov Chain Monte Carlo (MCMC) simulation has been presented for efficient collapse response assessment of the independent intake water tower. The intake tower is significantly used as a diversion type of the hydropower station for maintaining power plant, reservoir and spillway tunnel. Therefore, the seismic fragility assessment of the intake tower is a pivotal component for estimating total system risk of the reservoir. In this investigation, an asymmetrical independent slender reinforced concrete structure is considered. The Bayesian Inference method provides the flexibility to integrate the prior information of collapse response data with the numerical analysis results. The preliminary information of risk data can be obtained from various sources like experiments, existing studies, and simplified linear dynamic analysis or nonlinear static analysis. The conventional lognormal model is used for plotting the fragility curve using the data from time history simulation and nonlinear static pushover analysis respectively. The Bayesian Inference approach is applied for integrating the data from both analyses with the help of MCMC simulation. The method achieves meaningful improvement of uncertainty associated with the fragility curve, and provides significant statistical and computational efficiency.

• 산업기술연구
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• 제21권A호
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• pp.7-14
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• 2001

In building structure, the story height can be minimized by providing openings in beams which serves for the utility equipments passing through. The dead space in false ceiling thus put to economical use in the form of a substantial reduction in materials and construction cost. In the case of steel structure, there is no critical risk in the structural strength because of reinforcing methods of stiffness and steel plate but in the case of reinforced concrete structure, proper provision should be made in designing these openings, otherwise there is a risk that these opening will possibly weaken the structural strength of the building frame to a critical degree. In this paper, for the numerical analysis of the reinforced concrete beams with circular opening in the web, expecting stress concentration of the circular opening, reinforcing methods were studied. Twenty test pieces with each different reinforcing methods were tested and their resisting forces were defined. From the numerical analysis and test results, the followings were founded;(1)high shear stress distributed around the openings reduce the shearing strength, (2)from the numerical analysis, the maximum tensile stress occurred at opening nodes 1,7, these phenomena were agreed with the test results, (3)reinforcing method around openings have to carried out for stopping diagonal cracks, and (4)both, by steel plate, and wire mesh, are effective reinforcing methods.

• 한국가구학회지
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• 제22권1호
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• pp.13-17
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• 2011

Recently, interest in indoor air quality is increasing. Especially, radon radioactivity among the indoor air is a well-known risk factor for lung cancer because of ionizing radiation in the form of ${\alpha}$-particles. This study was carried out to investigate effect of black charcoal and activated carbon for reduction of radon radiation that emitted from building materials. Black charcoal and activated carbon were used as a barrier which was against the infiltration of radon. The source of radon was gypsum board. Two types of charcoal barrier were powder- and board-type with 5 mm, 10 mm thickness respectively. The method for this determination is evaluated radon concentration in chamber. The measurements were performed with radon detector, SARAD3120. Results of this study are as following: Black charcoal and activated carbon confirmed the highly efficient barrier. Radon concentration was reduced from 72% to 85% as compared the control chamber. Radon reduction capability, however, was no difference as barrier's types. Results obtained in ventilation condition, radon concentration shows 5.93 pCi/L on average in the closed condition and shows 2.69 pCi/L in the opened condition.

• 한국안전학회지
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• 제33권5호
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• pp.141-149
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• 2018

In a PCB factory, there is a corrosive chemical substance supply system that can causes major leakage accidents. These accidents can give rise to shut down the factory and do residents damage that cause enormous loss of properties. To mitigate these risks, it is necessary to provide a chemical disaster prevention system. Moreover, after considering the situation and environment of the production site, it is of great importance to build an optimal chemical accident prevention system by reflecting risk reduction measures from the point of process design and by assessing quantitative risk based on reliability data. However, because there was no established database of the reliability about facilities and equipment that can be used in the domestic, the business site and consulting organization had being used the reliability data such as USA CCPS(Center for Chemical Process Safety). In these days, Korean institutes are studying on reliability data utilization method of quantitative risk assessment for preventing chemical accidents and domestic utilization algorithms and storage bed of reliability data. This study presents samples of reliability database about the chemical substance supply system that constructed from the history data such as failure, maintenance for 10 years at a PCB factory. Also, this work proposes the safety design criteria for supply facilities of corrosive chemical substance by assessing quantitative risk on the basis of the reliability data.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.707-712
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• 2014

Purpose: Anastomotic leakage (AL) is associated with high morbidity and mortality, high reoperation rates, and increased hospital length of stay. Here we investigated the risk factors for AL after anterior resection for rectal cancer with a double stapling technique. Patients and Methods: Data for 460 patients who underwent primary anterior resection with a double stapling technique for rectal carcinoma at a single institution from 2003 to 2007 were prospectively collected. All patients experienced a total mesorectal excision (TME) operation. Clinical AL was defined as the presence of leakage signs and confirmed by diagnostic work-up according to ICD-9 codes 997.4, 567.22 (abdominopelvic abscess), and 569.81 (fistula of the intestine). Univariate and logistic regression analyses of 20 variables were undertaken to determine risk factors for AL. Survival was analysed using the Cox regression method. Results: AL was noted in 35 (7.6%) of 460 patients with rectal cancer. :Median age of the patients was 65 (50-74) and 161 (35%) were male. The diagnosis of AL was made between the 6th and 12th postoperative day (POD; mean 8th POD). After univariate and multivariate analysis, age (p=0.004), gender (p=0.007), tumor site (p<0.001), preoperative body mass index (EMI) (p<0.001), the reduction of TSGF on 5th POD less than 10U/ml (p=0.044) and the pH value of pelvic dranage less than or equal to 6.978 on 3rd POD (p<0.001) were selected as 6 independent risk factors for AL. It was shown that significant differences in survival of the patients were AL-related (p<0.001), high ASA score related (p=0.036), high-level EMI related (p=0.007) and advanced TNM stage related

• 한국심리학회지 : 문화 및 사회문제
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• 제22권3호
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• pp.387-410
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• 2016

본 연구에서는 위험과 안전에 대해 실존심리학적 관점의 고찰을 실시하였다. 실존주의 철학과 실존주의 심리학적 논의들을 통해서 실존적 과제로서 '위험'을 파악하였으며, 실존적 욕구로서 '안전'을 규정하였다. 나아가 실존적 과제의 미해결성과 실존적 욕구의 비충족성으로 인해 발생되는 실존적 불안으로서 '주관적 위험'을 파악할 수 있음을 제시하였다. 또한, 실존적 불안으로서 '주관적 위험'은 '위험'과 '안전'에 대한 실존적 직면과 완성으로 나아가게 하는 나침판으로서 역할을 하고 있음과 발현된 현상적 상태를 통해 문제적 고착 상태에 놓여 있음을 파악할 수 있는 신호로서의 기능을 수행하고 있음을 밝혔다. 그리고 실존적 불안으로서 '주관적 위험'의 문제적 고착 양상은 발현된 현상에 대칭적인 특성과 상태로 인식될 수 있는 경험과 정보를 공급하는 방법을 통해서 조절할 수 있음을 제안하였다. 실존심리학적 관점으로 '위험'과 '안전'을 파악하려는 시도는 세월호 참사를 비롯한 한국 사회의 인재형 사고에 대해 보다 근원적인 원인 분석과 대책을 마련해 줄 수 있을 것이라고 생각한다. 이를 통해 향후 위험 감소와 안전 향상을 위한 심리학적인 접근을 보다 다양한 방면에서 효과적으로 적용할 수 있는 시사점을 제시해 줄 수 있을 것이다. 또한, 본 연구를 통해 제시된 여러 견해들을 종합해서 다양한 실존적 주제들의 상태를 조절하는 방법[주제상태조절이론(Theme Condition Adjustment Theory: TCAT)]에 대한 이론적 토대를 마련할 수 있을 것이라고 기대한다.

• 경영정보학연구
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• 제17권1호
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• pp.117-140
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• 2015

클라우드 서비스는 10대 IT 전략기술 트렌드로 주목받고 있지만 국내 중소기업의 경우 대부분 비용 제약의 문제로 보안 위험이 높은 퍼블릭 클라우드를 사용하고 대기업에 비해 클라우드 서비스에 대한 이해도가 낮으며 도입률 또한 저조한 편이다. 한편 IT 프로젝트에서의 불확실성을 헷징하기 위한 방편으로 실물옵션 전략이 주목을 받고 있는데 본 연구에서는 클라우드 서비스의 기술적, 안전성, 관계적, 경제적 위험요소 간의 인과관계를 밝히고 경제적 위험이 실물옵션 채택의도에 어떠한 영향을 주는지에 관한 연구를 실시하였다. 본 연구는 전문업체에 의뢰하여 클라우드 서비스를 사용하고 있는 수도권 내 중소기업을 대상으로 설문조사를 실시하였다. 총 287부를 120개의 기업별로 평균을 내어 조직수준에서 분석을 하였으며 통계적 분석에는 Smart PLS Version 2.0.M3과 SPSS Statistics18을 활용하였다. 연구결과에 의하면 클라우드 서비스의 기술적 위험은 안전성 위험에 유의한 정(+)의 영향을 미쳤고 클라우드 서비스의 관계적 위험은 경제적 위험에 유의한 정(+)의 영향을 미쳤다. 그리고 클라우드 서비스의 안전성 위험은 경제적 위험에 유의한 정(+)의 영향을 미쳤고 경제적 위험은 연기옵션과 포기옵션 채택의도에 유의한 정(+)의 영향을 미쳤다. 본 연구는 클라우드 서비스를 사용함으로써 겪을 수 있는 여러 위험 요인을 세분화하고 위험 요인과 실물옵션간의 관계를 명확히 밝힘으로써 클라우드 서비스 계약 시에 실물옵션을 적용할 수 있는 이론적인 바탕이 될 수 있게 하였다. 실무적으로는 클라우드 서비스를 사용함에 있어 발생할 수 있는 여러 위험들을 효과적으로 관리하고 통제하기 위하여 클라우드 서비스 계약 시 이들 위험들을 관리할 수 있는 실물옵션을 계약사항에 제시함으로써 사용자와 공급자 모두에게 도움이 될 수 있는 전략을 세울 수 있다는 데에 의의가 있다.

• 한국분무공학회지
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• 제6권4호
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• pp.1-13
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• 2001

In the pesticides sprays, spray and atomization technologies to increase the deposition and reduce the drift are briefly reviewed. Further research is needed to deduce a measure of drift risk in sprays with different structures, velocity profiles. For flat fan nozzles, the data of breakup length and thickness of liquid sheet are essential to understand the atomization processes and develop the transport model to target. In the air-assisted spray technology to reduce drift, further works on the effect of application height on drift and air assistance on droplet size should be followed. In addition, methods for quantifying included air in the air inclusion techniques are required. A few researches on the droplet size of fallout can be found in the literature. A combined technology with electrostatic method into one of method for the reduction of drift may be an effective strategy for increasing deposition and reducing drift.