• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6563-6568
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• 2013

Background: Tobacco use and quit attempts are two key indicators of the Global Adult Tobacco Survey (GATS) that assess quit attempts among current as well as former tobacco users. The relevant data have inherent policy implications for tobacco cessation programme evaluation. This study aimed to review the concepts of quit attempt assessment and quantifying invalid responses considering GATS-India data. Materials and Methods: GATS assessment of tobacco use and quit attempts were examined in the current literature. Two categories of invalid responses were identified by stratified analysis of the duration of last quit attempt among current users and duration of abstinence among former users. Category A included absolute invalid responses when time-frame of assessment of current tobacco use and less than former tobacco use were violated. Category B included responses that violated the unit of measurement of time. Results: Current daily use, current less than daily use and former use in GATS were imprecisely defined with overlapping of time-frame of assessment. Overall responses of 3,102 current smokers, 4,036 current smokeless users, 1,904 former smokers and 1,343 former smokeless users were analyzed to quantify invalid responses. Analysis indicated overall 21.2% (category A: 7.32%; category B: 17.7%) and 22.7% (category A: 8.05%; category B: 18.1%) invalid responses among current smokers and smokeless users respectively regarding their duration of last quit attempt. Similarly overall 6.62% (category A: 4.7%; category B: 2.3%) and 10.6% (category A: 8.6%; category B: 3.5%) invalid responses were identified among former smokers and smokeless users respectively regarding their duration of abstinence. Conclusions: High invalid responses for a single assessment are due to the imprecise definition of current use, former use and quit attempt; and failure to utilize opportunity of direct data entry interface use during the survey to validate responses instantly. Redefining tobacco use and quit attempts considering an appropriate timeframe would reduce invalid responses.

• Steel and Composite Structures
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• 제47권2호
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• pp.167-184
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• 2023

In this study, a new recentering friction device (RFD) to retrofit steel moment frame structures is introduced. The device provides both self-centering and energy dissipation capabilities for the retrofitted structure. A hybrid performance-based seismic design procedure considering multiple limit states is proposed for designing the device and the retrofitted structure. The design of the RFD is achieved by modifying the conventional performance-based seismic design (PBSD) procedure using computational intelligence techniques, namely, genetic algorithm (GA) and artificial neural network (ANN). Numerous nonlinear time-history response analyses (NLTHAs) are conducted on multi-degree of freedom (MDOF) and single-degree of freedom (SDOF) systems to train and validate the ANN to achieve high prediction accuracy. The proposed procedure and the new RFD are assessed using 2D and 3D models globally and locally. Globally, the effectiveness of the proposed device is assessed by conducting NLTHAs to check the maximum inter-story drift ratio (MIDR). Seismic fragilities of the retrofitted models are investigated by constructing fragility curves of the models for different limit states. After that, seismic life cycle cost (LCC) is estimated for the models with and without the retrofit. Locally, the stress concentration at the contact point of the RFD and the existing steel frame is checked being within acceptable limits using finite element modeling (FEM). The RFD showed its effectiveness in minimizing MIDR and eliminating residual drift for low to mid-rise steel frames models tested. GA and ANN proved to be crucial integrated parts in the modified PBSD to achieve the required seismic performance at different limit states with reasonable computational cost. ANN showed a very high prediction accuracy for transformation between MDOF and SDOF systems. Also, the proposed retrofit showed its efficiency in enhancing the seismic fragility and reducing the LCC significantly compared to the un-retrofitted models.

• Steel and Composite Structures
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• 제30권3호
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• pp.201-215
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• 2019

In this research, the behavior of tube-in-tube BRBs (TiTBRBs) has been investigated. In a typical TiTBRB, the yielding core tube is located inside the outer restraining one to dissipate energy through extensive plastic deformation, while the outer restraining tube remains essentially elastic. With the aid of FE analyses, the monotonic and cyclic behavior of the proposed TiTBRBs have been studied as individual brace elements. Subsequently, a detailed finite element model of a representative single span-single story frame equipped with such a TiTBRB has been constructed and both monotonic and cyclic behavior of the proposed TiTBRBs have been explored under the application of the AISC loading protocol at the braced frame level. With the aid of backbone curves derived from the FE analyses, a simplified frame model has been developed and verified through comparison with the results of the detailed FE model. It has been shown that, the simplified model is capable of predicting closely the cyclic behavior of the TiTBRB frame and hence can be used for design purposes. Considering type of connection detail used in a frame, the TiTBRB member which behave satisfactorily at the brace element level under cyclic loading conditions, may suffer global buckling due to the flexural demand exerted from the frame to the brace member at its ends. The proposed TiTBRB suit tubular members of offshore structures and the application of such TiTBRB in a typical offshore platform has been introduced and studied in a single frame level using detailed FE model.

• Structural Engineering and Mechanics
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• 제59권4호
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• pp.653-669
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• 2016

Recent earthquakes worldwide show that a significant portion of the earthquake shaking happens in the vertical direction. This phenomenon has raised significant interests to consider the vertical ground motion during the seismic design and assessment of the structures. Strong vertical ground motions can alter the axial forces in the columns, which might affect the shear capacity of reinforced concrete (RC) members. This is particularly important for non-ductile RC frames, which are very vulnerable to earthquake-induced collapse. This paper presents the detailed nonlinear dynamic analysis to quantify the collapse risk of non-ductile RC frame structures with varying heights. An array of non-ductile RC frame architype buildings located in Los Angeles, California were designed according to the 1967 uniform building code. The seismic responses of the architype buildings subjected to concurrent horizontal and vertical ground motions were analyzed. A comprehensive array of ground motions was selected from the PEER NGA-WEST2 and Iran Strong Motions Network database. Detailed nonlinear dynamic analyses were performed to quantify the collapse fragility curves and collapse margin ratios (CMRs) of the architype buildings. The results show that the vertical ground motions have significant impact on both the local and global responses of non-ductile RC moment frames. Hence, it is crucial to include the combined vertical and horizontal shaking during the seismic design and assessment of non-ductile RC moment frames.

• Steel and Composite Structures
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• 제26권5호
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• pp.549-556
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• 2018

Progressive building collapse occurs when failure of a structural component leads to the failure and collapse of surrounding members, possibly promoting additional failure. Global system collapse will occur if the damaged system is unable to reach a new static equilibrium configuration. The most common type of primary failure which led to the progressive collapse phenomenon, is the sudden removal of a column by various factors. In this study, a method is proposed to prevent progressive collapse phenomena in structures subjected to removal of a single column. A vierendeel peripheral frame at roof level is used to redistribute the removed column's load on other columns of the structure. For analysis, quasi-static approach is used which considers various load combinations. This method, while economically affordable is easily applicable (also for new structures as well as for existing structures and without causing damage to their architectural requirements). Special emphasis is focused on the evolution of vertical displacements of column removal point. Even though additional stresses and displacements are experienced by removal of a structural load bearing column, the proposed method considerably reduces the displacement at the mentioned point and prevents the collapse of the structural frame.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.30-37
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• 2020

In the building construction, the steel-frame work occupies an important position in terms of structure, cost and quality. Especially in Japan, steel frames have traditionally been the main structure of many buildings. For steel-frame works in such positions, this paper investigates an existing steel fabricator to clarify the actual conditions of design decision making process and management method in steel production process. This study focuses on a steel fabricator (Company M in the following sentences), whose main market is Japan and which has facilities in Thailand, China, and Japan. Company M uses QR codes to control the production status of products, and exchanges all information between inside and outside the company via specialized departments in the form of documents. The authors have already analyzed the relationship between production lead time and defect rate based on actual project data at Architectural Institute of Japan in 2016. In 2019, we expressed the process from the confirmation of the design information of the current steel frame to the production by WBS, and clarified the relationship between the production lead time and steel frame product quality structurally. In this paper, the authors reoport the progress of the survey conducted so far, the positioning of the collected data, and the future survey policy.

• 한국통신학회논문지
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• 제41권8호
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• pp.843-850
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• 2016

This paper introduces a novel modulation scheme for vehicular communication in taking advantage of existing LED lights available on a car. Our proposed 2-Phase Shift Keying (2-PSK) is a spatial modulation approach in which a pair of LED light sources in a car (either rear LEDs or front LEDs) is used as a transmitter. A typical camera (i.e. low frame rate at no greater than 30fps) that either a global shutter camera or a rolling shutter camera can be used as a receiver. The modulation scheme is a part of our Image Sensor Communication proposal submitted to IEEE 802.15.7r1 (TG7r1) recently. Also, a neural network approach is applied to improve the performance of LEDs detection and decoding under the noisy situation. Later, some analysis and experiment results are presented to indicate the performance of our system

• 디지털융복합연구
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• 제12권5호
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• pp.57-68
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• 2014

이 글은 한국에서 시기별 개인정보 유출에 대한 프레임이 어떤 형태로 변화하는지에 초점을 맞추고 있다. 이를 위하여 개인정보 유출이라는 텍스트가 등장하기 시작한 1984년도부터 현재까지 30년 간 걸쳐 보도된 신문기사의 제목을 수집하였다. 시기마다 형성되어 있는 지배적인 프레임을 도출하기 위하여 단순 빈도분석과 공동출현빈도 매트릭스 기반의 텍스트 네트워크 분석, 군집분석을 실시하였다. 사회연결망분석의 주요 지표인 연결중심성의 개념을 적용하여 시기별 주된 프레임을 밝혀내었다. 총 4시기에 걸쳐 프레임의 태동, 형성, 확장, 전환의 과정이 일어났는데, 개인정보에 대한 접근 및 보유주체가 주로 정부였다면 점차 전자상거래 등 고객맞춤형 서비스로 인해 민간 기업으로 확대되었다. 또한 초국가기업의 등장은 개인정보 유출의 경계를 자연스럽게 국내에서 국외로 확장시켰다. 빅데이터 시대의 엄청난 정보량과 데이터 생태계의 역동성은 새로운 정보보안위협으로 다가오고 있어 강력한 정보보호체계 설계가 시급함을 프레임의 전환을 통하여 보여주고 있다.

• Structural Monitoring and Maintenance
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• 제1권4호
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• pp.427-449
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• 2014

A hybrid optimization method for the identification of state-space models is presented in this study. Hybridization is succeeded by combining the advantages of deterministic and stochastic algorithms in a superior scheme that promises faster convergence rate and reliability in the search for the global optimum. The proposed hybrid algorithm is developed by replacing the original stochastic mutation operator of Evolution Strategies (ES) by the Levenberg-Marquardt (LM) quasi-Newton algorithm. This substitution results in a scheme where the entire population cloud is involved in the search for the global optimum, while single individuals are involved in the local search, undertaken by the LM method. The novel hybrid identification framework is assessed through the Monte Carlo analysis of a simulated system and an experimental case study on a shear frame structure. Comparisons to subspace identification, as well as to conventional, self-adaptive ES provide significant indication of superior performance.

• 한국융합학회논문지
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• 제8권3호
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• pp.295-306
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• 2017

본 연구는 외국인 운동선수 귀화 현상이 언론보도를 통해 형성되는 프레임을 분석하는 데 목적이 있었다. 이를 위하여 한국언론진흥재단 'Korea Integrated Database System'(KINDS, http://www.bigkinds.or.kr)을 활용하여 경향신문, 세계일보, 한겨레신문, 한국일보, MBC, SBS, YTN의 2014년부터 2016년까지 3년간 외국인 운동선수의 특별귀화와 관련된 보도 총 101건을 분석하였다. 연구 결과, 단순 사실보도 프레임에서는 특정 선수의 귀화사실, 경기 출전 및 입상 관련 정보가 전달되었고, 경제성 프레임의 경우 외국인 특별귀화로 얻을 수 있는 이익을 통해 귀화의 정당성이 뒷받침되고 있었다. 인간적 흥미 프레임에서는 외국인 귀화 선수들의 성장과 귀화 과정, 삶과 애로 등이 보도되었으며, 갈등 프레임의 경우 파란눈 국가대표들의 대표성 문제, 국내 선수육성의 인과성, 국내 프로리그 복귀로 인한 리그 규정의 혼성 등이 주로 보도되었다. 도덕성 책임귀인 프레임은 주로 2016년 첼시 리의 특별귀화 서류조작 사건을 통한 귀화선수의 도덕성과 법적 후속조치 등이 보도되었다.