• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.31-40
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• 1999

The bracing system using screw jack is not effective for the restraining of adjacent ground displacement. since the screw jack dose not induce sufficient preloading on struts. In order to protect excessive displacement of adjacent ground at braced excavation, new preloading jack was developed in the country. In this paper, the new preloading jack and the measurement results of the lateral displacement of braced wall at three deep excavation sites in Seoul city are introduced. The measurement results showed that the maximum displacements of braced wall are smaller than 0.15% of excavation depth, therefore the wall displacements can be minimized by preloading which is acted on bracing. If the bracing system with new preloading jack is used in braced excavation, it is effective for reducing the cost and period of construction.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.25-32
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• 2007

Automobile manufacturing companies should provide the products and service that can satisfy consumers who usually want various kinds of automobiles. This paper studied the relations among several demographic characteristics(gender, age, occupation, income) of consumers and automobile's attributes(engine performance, engine displacement, price, maintenance expenses, color, etc.) and preferred automobile(kind, size, company, price). For the relation research we established a model and related hypotheses and used a questionnaire survey, where 350 subjects were questioned. After the analysis, many statistically significant results are obtained : consumer's gender has relations with the preference for engine performance, engine displacement, price, color, and design; age has relations with the preference for engine displacement, maintenance expenses, free checking during A/S period, etc., occupation has relations with the preference for engine performance, engine displacement, price, maintenance expenses, fuel efficiency, etc. : income has relations with the preference for engine performance, engine displacement, price, maintenance expenses, mileage, reputation of car manufacturing companies, etc.; price and fuel efficiency has relations with the preference for car manufacturing companies. These results suggest the consumer-oriented sales of automobiles and are expected to be helpful for the effective strategy development of automobile marketing.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.267-275
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• 2009

According to the recent statistics of marine casualties in Korea, fishing boats are more likely to be ended in the casualties, and small fishing boats especially cause much more accidents in sinking and capsizing than any other big vessels. These casualties were mainly produced from the ignorance on the lack of own ship stability. From this view, this study aims to analyze the characteristics of stability on the crab trap fishing boat receiving transverse wave by means of carrying out the water tank test. The rolling angle of the model ship was affected largely with the displacement and the wave period of it, and the trends were shown that the magnitude of the angle was proportional to the displacement, but inversely to the wave period. And the wave height had effect on the rolling angle just in the specific range of the wave period. The force of steady wind didn't have influence on the rolling variation significantly.

• Journal of the Earthquake Engineering Society of Korea
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• v.28 no.4
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• pp.165-170
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• 2024

This study investigated the impact of soil-structure interaction on multi-degree-of-freedom structures using the shallow-foundation Winkler model, known as the BNWF model. The model's period was determined through eigenvalue analysis and compared to results obtained from FEMA's formula. Results indicated that considering the soil, the structure's period increased by up to 8.7% compared to the fixed-base model, aligning with FEMA's calculations. Furthermore, with adequate ground acceleration, roof displacement increased by 3.4% to 3.8%, while base shear decreased by 4% to 10%. However, roof displacement and base shear increased in some earthquake scenarios due to spectral shape effects in regions with extended structural periods. Foundation damping effects, determined through the foundation's moment-rotation history, grew with higher ground acceleration. This suggests that accounting for period elongation and foundation damping can enhance the seismic design of multi-degree-of-freedom structures.

• Smart Structures and Systems
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• v.20 no.4
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• pp.397-413
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• 2017

Precast concrete (PC) members are currently being employed for general construction or partial replacement to reduce construction period. As assembly work in PC construction requires connecting PC members accurately, measuring the 6-DOF (degree of freedom) relative displacement is essential. Multiple planar markers and camera-based displacement measurement systems can monitor the 6-DOF relative displacement of PC members. Conventional methods, such as direct linear transformation (DLT) for homography estimation, which are applied to calculate the 6-DOF relative displacement between the camera and marker, have several major problems. One of the problems is that when the marker is partially hidden, the DLT method cannot be applied to calculate the 6-DOF relative displacement. In addition, when the images of markers are blurred, error increases with the DLT method which is employed for its estimation. To solve these problems, a hybrid method, which combines the advantages of the DLT and MCL (Monte Carlo localization) methods, is proposed. The method evaluates the 6-DOF relative displacement more accurately compared to when either the DLT or MCL is used alone. Each subsystem captures an image of a marker and extracts its subpixel coordinates, and then the data are transferred to a main system via a wireless communication network. In the main system, the data from each subsystem are used for 3D visualization. Thereafter, the real-time movements of the PC members are displayed on a tablet PC. To prove the feasibility, the hybrid method is compared with the DLT method and MCL in real experiments.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.126-133
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• 2021

Axial displacement of an implant-supported prosthesis is frequently reported in clinical and laboratory studies. However, limited information is available about the behavior of the axial displacement of implant-supported prostheses functioning in intraoral situations. The present case report evaluated the three-dimensional displacement of posterior single implant-supported prostheses in 2 different patients. Internal connection type implants were placed, and screw and cement-retained prosthesis (SCRP) type prosthesis were delivered after an appropriate healing period. Intraoral digital scans were performed using an intraoral scanner (Cerec Omnicam, Dentsply Sirona, USA) on the day of crown delivery and one week, one month, and one year after delivery. The amount of 3-dimensional displacement of the prosthesis was evaluated by using a digital inspection software (Geomagic Control X, 3D systems, USA). The axial displacement of implant-supported prosthesis occurred in both patients. Furthermore, the amount of displacement increased over time.

• Korean Journal of Remote Sensing
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• v.30 no.2
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• pp.161-172
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• 2014

Established in the lower reaches of the Nakdong river in Busan, the Noksan national industrial complex is one of the deepest soft ground areas in Korea. In case of the costal landfill having deep soft ground, there is a significant residual settlement over a long period of time. In this study, there was observed ground subsidence occurred in the Noksan national industrial complex from September 2002 to April 2007 by applying DInSAR and SBAS time series method using RADARSAT-1 and Envisat SAR datasets. As a result, it was calculated that ground subsidence developed at the velocity of about maximum 10 cm/yr and mean 6 cm/yr at the eastern center, west, western center and southern area contiguous on the coastline of the study area during the period from September 2002 to April 2007. In addition, the RADARSAT-1 average displacement map has been compared with the total displacement map observed by accurate magnetic probe extensometer during the period from 2001 to 2002. Since the time series displacement has shown a linear trend mostly, we consider that continuous monitoring should be needed until the ground subsidence of the study area has been stabilized.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.114-123
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• 2012

This study is aimed to assess the stability of cable bridge by determining the geometric shape of the suspension bridge among the domestic coastal structures in public use after their completion of construction and the displacement of the target suspension bridge after public use. For this purpose, this study calculated the length between pylon piers for each period, sag, sag ratio and the displacement of pylon. Compared to the management standards for each step across different pylon behaviors of the target suspension bridge, this study found that the target suspension bridge behaves stably within the maintenance standards. To identify the behaviors of a suspension bridge accurately, the priority is put on the determination of geometric shape. Therefore, it is required to determine the surveyed shape model on a regular basis across public use period and increased traffics, which is expected to contribute considerably to ensuring the stability of the suspension bridge in its maintenance.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.5
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• pp.259-264
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• 2016

Objectives: We evaluated and recorded post-traumatic and postoperative neurosensory deficits of the inferior alveolar nerve (IAN) in mandibular fracture in order to identify associated risk factors. Materials and Methods: This was a prospective cohort study composed of 60 patients treated for mandibular fracture. The primary study variable was the change between the post-traumatic IAN neurosensory examination score and the score after fracture reduction. Risk factors were categorized as demographic, anatomic, fracture displacement, and treatment. Appropriate descriptive and bivariate statistics were computed. Results: Sixty patients with unilateral mandibular fracture reported within 24 hours of injury were evaluated over a one-year period. A post-traumatic neurosensory deficit was observed in 52 patients (86.7%), the percentage of which was reduced to 23.3% over the follow-up period. Abnormal postoperative neurosensory scores were significantly higher in angle fracture cases (33.3%) compared to body fracture cases (11.1%). When recovered and non-recovered neurosensory scores were compared by fracture location, 88.9% of body fracture cases showed significant recovery compared to 66.7% of mandibular angle fracture cases. Cases with less than 5 mm fracture displacement showed statistically significantly higher neurosensory recovery scores (90.6%) compared to those with more than 5 mm fracture displacement (60.7%). Conclusion: Use of a miniplate with mono-cortical screws does not play a role in increasing IAN post-traumatic neurosensory deficit. Early management can reduce the chances of permanent neurosensory deficit. Mandibular fracture displacement of 5 mm or more and fracture location were found to be associated with an increased risk of post-traumatic IAN neurosensory score worsening.

• Earthquakes and Structures
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• v.18 no.4
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• pp.467-480
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• 2020

Concrete rectangular liquid storage tanks are widely used, but there are many cases of damage in previous earthquakes. Nonlinear fluid-structure interaction (FSI) is considered, Mooney-Rivlin material is used for rubber bearing, nonlinear contact is used for sliding bearing, numerical calculation models of no-isolation, rubber isolation, sliding isolation and hybrid isolation concrete rectangular liquid storage tanks are established; dynamic responses of different structures are compared to verify the effectiveness of isolation methods; and influences of earthquake amplitude, bidirectional earthquake and far-field long-period earthquake on dynamic responses are investigated. Results show that for liquid sloshing wave height, rubber isolation cause amplification effect, while sliding isolation and hybrid isolation have reduction effect; displacement of rubber isolation structure is much larger than that of sliding isolation with limiting-devices and hybrid isolation structure; when PGA is larger, wall cracking probability of no-isolation structure becomes larger, and probability of liquid sloshing wave height and structure displacement of rubber isolation structure exceeds the limit is also larger; under bidirectional earthquake, occurrence probabilities that liquid sloshing wave height and structure displacement of rubber isolation structure exceed the limit will be increased; besides, far-field long-period earthquake mainly influences structure displacement and liquid sloshing wave height. On the whole, control effect of sliding isolation is the best, followed by hybrid isolation, and rubber isolation is the worst.