• Computers and Concrete
• /
• 제16권1호
• /
• pp.99-123
• /
• 2015

In this study, structural vulnerability of reinforced concrete moment resisting frames (RC-MRFs) by considering the Iran-specific characteristics is investigated to manage the earthquake risk in terms of multicomponent seismic excitations. Low and medium rise RC-MRFs, which constitute approximately 80-90% of the total buildings stock in Iran, are focused in this fragility-based assessment. The seismic design of 3-12 story RC-MRFs are carried out according to the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800), and the analytical models are formed accordingly in open source nonlinear platforms. Frame structures are categorized in three subclasses according to the specific characteristics of construction practice and the observed seismic performance after major earthquakes in Iran. Both far and near fields' ground motions have been considered in the fragility estimation. An optimal intensity measure (IM) called Sa, avg and beta probability distribution were used to obtain reliable fragility-based database for earthquake damage and loss estimation of RC buildings stock in urban areas of Iran. Nonlinear incremental dynamic analyses by means of lumped-parameter based structural models have been simulated and performed to extract the fragility curves. Approximate confidence bounds are developed to represent the epistemic uncertainties inherent in the fragility estimations. Consequently, it's shown that including vertical ground motion in the analysis is highly recommended for reliable seismic assessment of RC buildings.

• 대한인간공학회지
• /
• 제34권5호
• /
• pp.427-436
• /
• 2015

Objective: This study aims to analyze occupational accidents of parking lot attendants by parking lot type. Background: Recently, efforts are made to analyze accident characteristics by occupation type targeting the workers engaged in the same work. Method: This study analyzes 303 occupational accidents of parking lot attendants occurring from 2010 to 2012. Parking lots are grouped into two groups according to the work environment. One is public/ground type which comprises road side or open area parking lots and the other is building/mechanical type which comprises a multi-story parking building with connecting ramps and/or mechanical parking system. The characteristics of occupational accidents by parking lot type are analyzed. Results: Accident characteristics showed the difference between public/ground type and building/mechanical type on the size of enterprise, age, gender and work experience of the injured. Also the accident type, source of accident and parts of body affected are different between the two parking lot types. Conclusion and Application: The findings of accident characteristics according to parking lot types can be used as baseline data for establishing systemized preventative policies for occupational accidents of parking lot attendants.

• 통상정보연구
• /
• 제12권4호
• /
• pp.171-192
• /
• 2010

In general, a stock index and its individual stocks are assumed to follow a random walk. A stock index is an important source of information and one that is seen by people everyday, regardless of their investment intentions. This paper examines the correlation between the KOSPI-the index that best reflects the Korean stock market and the macro - economic variables that have been found to influence the index by previous studies. The sample period considers the years after 2000 when the Korean stock market matured as restrictions on foreign investors were removed. For this purpose, a Vector Error Correction Model (VECM) and KOSPI equation with a general pacific approach were used. This paper aims at verifying the factors that determined the KOSPI after 2000 and at examining whether there was structural change in the investment environment. It also investigates changes in the factors determining the KOSPI's performance as a result of structural changes in the investment environment. The V AR (Vector Autoregressive) model including the nine variables was selected as a baseline model whose stability was tested using the unit root test. The results from the VECM and the structural changes in the investment environment can be summarized by the following Inner story points.

• Earthquakes and Structures
• /
• 제8권3호
• /
• pp.591-617
• /
• 2015

Standards for seismic assessment and retrofitting of buildings provide deformation limit states for structural members and connections. However, in order to perform fully consistent performance-based seismic analyses of soil-structure systems; deformation limit states must also be available for foundations that are vulnerable to nonlinear actions. Because such limit states have never been established in the past, a laboratory testing program was conducted to study the rotational capacity of small-scale foundation models under combined axial load and moment. Fourteen displacement-controlled monotonic and cyclic tests were performed using a cohesionless soil contained in a $2.0{\times}2.0{\times}1.2m$ container box. It was found that the foundation models exhibited a stable hysteretic behavior for imposed rotations exceeding 0.06 rad and that the measured foundation moment capacity complied well with Meyerhof's equivalent width concept. Simplified code-based soil-structure analyses of an 8-story building under an array of strong ground motions were also conducted to preliminary evaluate the implication of finite rotational capacity of vulnerable foundations. It was found that for the same soil as that of the experimental program foundations would have a deformation capacity that far exceeds the imposed rotational demands under the lateral load resisting members so yielding of the soil may constitute a reliable source of energy dissipation for the system.

• 유통과학연구
• /
• 제17권1호
• /
• pp.47-56
• /
• 2019

Purpose - This case study illustrates the story of eBay Korea, which owns two most leading Korean open market companies, AUCTION and Gmarket. The main concerns are to take over the Korean top domestic companies one by one, then, emerge these two giants through its well-developed post-merger Integration by eBay, an American multinational corporation. Research design, data, and methodology - This case explores various secondary resources such as periodicals, annual reviews, magazine, news articles, commentaries, even some interview materials related to 'eBay Korea' and industry source on condition of anonymity based on the critical reviewing of existing studies on these topics as well. Results - The findings of this study show the merger and acquisition of two market leaders in Korea is the only successful case in Asian Markets. The eBay's choice of entry mode is appropriate considering the timing, synergy and efficiency by sharing their resources. Conclusions - This study examines the successful entry and settlement process of foreign, multinational company through mergers and acquisitions in the Korean market. This would be a valuable in the studies of International Business and Global entry or distribution strategy in the e-commerce and open market dealing with M&A and its post-merger integration.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2019년도 학술발표회
• /
• pp.218-218
• /
• 2019

Jeju island has an area of $1,810km^2$ and is considered the largest island in South Korea. In Jeju Island the average annual precipitation is 1,957mm. About 54% of precipitation is estimated to be lost due to evapo-transpiration and direct runoff, and the remainder is recharged. Historically springs and puddles were the island's primary sources of water. However, after 1970 all sectors, including the urban and industrial sectors depended solely on groundwater as their water resource. As vast amount of water is being recharged the Island has many springs, especially near the coastlines. Historlcally, spring of Jeju Island formed village and make it possible to continue a life. Also it produces many values such as the spring related story, culture, tourism and ecosystems. Especially, the naturally rare phenomenon that about 900 springs appear over the whole area of Jeju Island makes it possible to call it as a natural heritage. As a result of this most springs have either been destroyed or been in the state of neglect. In some cases it has been observed that springs were preserved by nature, however majority of the cases saw springs losing their own nature as a result of abandonment. It was recorded that there were 911 springs in Jeju Island with most of them being distributed along the coast, which consequently increases their susceptibility to seawater intrusion. The objective of this study is therefore to analyze Eco-cultural and Engineering characteristics about springs in the island, highlighting its past utilization and reestablishing its potential as a source of spring.

• Structural Engineering and Mechanics
• /
• 제77권4호
• /
• pp.463-472
• /
• 2021

Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.

• Structural Engineering and Mechanics
• /
• 제82권5호
• /
• pp.611-628
• /
• 2022

Energy-dissipative rocking (EDR) columns are a class of seismic mitigation device capable of dissipating seismic energy and preventing weak-story failure of moment resisting frames (MRFs). An EDR consists of two hinge-supported steel columns interconnected by steel dampers along its height. Under earthquakes, the input seismic energy can be dissipated by plastic energy of the steel dampers in the EDR column. However, the unrecoverable plastic deformation of steel dampers generally results in residual drifts in the structural system. This paper presents a proof-of-concept study on an innovative device, namely self-centring energy-dissipative rocking (SC-EDR) column, aiming at enabling self-centring capability of the EDR column by installing a set of shape memory alloy (SMA) tension braces. The working mechanism of the SC-EDR column is presented in detail, and the feasibility of the new device is carefully examined via experimental and numerical studies considering the parameters of the SMA bar diameter and the steel damper plate thickness. The seismic responses including load carrying capacities, stress distributions, base rocking behaviour, source of residual deformation, and energy dissipation are discussed in detail. A rational combination of the steel damper and the SMA tension braces can achieve excellent energy dissipation and self-centring performance.

• Structural Engineering and Mechanics
• /
• 제82권6호
• /
• pp.735-745
• /
• 2022

The suspension thyristor valve can generate tremendous vertical acceleration responses in layers and large tension forces in hangers. A shaking table test of a scaled-down model of thyristor valves suspended on a hall building is performed to qualify the risk of vertical uplift of two representative types of valves, the chain valve and the rigid valve. Besides, an analytical model is established to investigate the source of the slackening of hangers. The test results show that the valves frequently experience a large vertical acceleration response. The soft spring joint can significantly reduce acceleration, but is still unable to prevent vertical uplift of the chain valve. The analytical model shows a stiffer roof and inter-story connection both contribute to a higher risk of vertical uplift for a rigid valve. In addition, the planar eccentricity and short hangers, which result in torsional motion of the valve, increase the possibility of vertical uplift for a chain valve. Therefore, spring joints with additional viscous dampers and symmetric layout in each layer are recommended for the rigid and chain valve, respectively, to prevent the uplift of valves.

• 수완나부미
• /
• 제5권2호
• /
• pp.29-39
• /
• 2013

This paper deals with the study of a manuscript on Rakhine history which is deposited today in Oriental and India Office Collection of the British Library as the accession number OR 3465 A. The External Criticism of this manuscript shows that it is a manuscript, which was commissioned Nga Mi to compile by Sir Arthur P. Phayre by making references of the existing Rakhine chronicles in the early colonial period, as Phayre wanted a historical account with an outline of the royal dynasties. The Internal Criticism reveals that the compiler Nga Mi did not invent the writing of his own but drawn the sources from various Rakhine chronicles in compiling his work. And Sir Arthur Phayre who used this Nga Mi Chronicle or OR 3465 A as the chief source in writing Rakhine history. He did not analyse the mythical, supernatural and improbable elements in Nga Mi Rakhine Razawin. Phayre did not problematicize any historical issue from Nga Mi Chronicle. One of the outstanding examples of the legend of King Min Saw Mon is discussed in this paper. As Arthur Phayre took this account from Nga Mi Chronicle and framed the story into a convincing narrative in his "History of Burma", the scholars after Phayre have continued to present the legend as a historical fact.