• Journal of the Ergonomics Society of Korea
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• v.30 no.5
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• pp.629-636
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• 2011

Objective: The aim of this study is developing an elderly automatic showering system by optimizing nozzle position and angle of water injection on ergonomics approach. Background: The elderly living in nursing home or hospital were increased by an aging population. Helping the elderly on showering is so hard. In addition, the existing showering/bathing systems are not effective because shower pattern of the elderly and washed range of nozzle were not considered. Method: Firstly, basic specification were determined by anthropometric approach. Secondly, position of nozzle and angle of water injection were determined through observation of elderly behavior on showering. And, finally, they were optimized by washing test and showering simulation. Results: On showering importance of body parts were able to analysis through observation of elderly behavior. The position of nozzle and angle of water injection was able to optimize by showering simulation. The automatic showering system was developed by considering their results. Conclusion: The most important technology of developing a showering system is the determining position of nozzle and angle of water injection, number of nozzle. It was developed by applying its results through user centered-research. Application: The user centered-research of developing products was able to apply directly to develop automatic bath, showering products etc. Further more it was available to apply senior friendly products.

• Journal of Electrical Engineering and Technology
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• v.7 no.3
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• pp.411-419
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• 2012

This paper proposes a new FDI(Fault Detection and Isolation) method, which is called EPSA(Extended Parity Space Approach). This method is particularly suitable for fault detection and isolation of the system with one faulty sensor or two faulty sensors. In the system with two faulty sensors, the fault detection and isolation probability may be decreased when two faults are occurred between the sensors related to the large fault direction angle. Nonetheless, the previously suggested FDI methods to treat the two-faults problem do not consider the effect of the large fault direction angle. In order to solve this problem, this paper analyzes the effect of the large fault direction angle and proposes how to increase the fault detection and isolation probability. For the increase the detection probability, this paper additionally considers the fault type that is not detected because of the cancellation of the fault biases by the large fault direction angle. Also for the increase the isolation probability, this paper suggests the additional isolation procedure in case of two-faults. EPSA helps that the user can know the exact fault situation. The proposed FDI method is verified through Monte Carlo simulation.

• ETRI Journal
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• v.33 no.4
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• pp.569-579
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• 2011

This paper presents a novel approach for human activity recognition (HAR) using the joint angles from a 3D model of a human body. Unlike conventional approaches in which the joint angles are computed from inverse kinematic analysis of the optical marker positions captured with multiple cameras, our approach utilizes the body joint angles estimated directly from time-series activity images acquired with a single stereo camera by co-registering a 3D body model to the stereo information. The estimated joint-angle features are then mapped into codewords to generate discrete symbols for a hidden Markov model (HMM) of each activity. With these symbols, each activity is trained through the HMM, and later, all the trained HMMs are used for activity recognition. The performance of our joint-angle-based HAR has been compared to that of a conventional binary and depth silhouette-based HAR, producing significantly better results in the recognition rate, especially for the activities that are not discernible with the conventional approaches.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.113-119
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• 2000

There are two major factors which affect the cam design : the pressure angle and the radius of curvature, Cam shape will have an instantaneous radius of curvature at every point. Even though the design constraint of the pressure angle has been satisfied the follower may still not complete the desired contact motion. If the radius of the follower roller is larger than the concave(negative) radius on the cam it occurs the gap between the cam and the follower roller at the contact point. And also if the curvature of the pitch curve of the cam is too sharp the cam profile may be undercut. This paper proposes a new approach which uses the relative velocity of the follower roller parallel to the tangent line at the contact point on the cam surface for determining the pressure angle and the relative acceeration for determining the radius of curvature.

• Earthquakes and Structures
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• v.17 no.4
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• pp.387-398
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• 2019

On the basis that ground motions may arrive at a structure from any horizontal direction and that different directions of seismic incidence would result in different structural dynamic responses, this paper focuses on orienting the crucial seismic incidence of transmission tower-line systems based on the wavelet energy method. A typical transmission tower-line system is chosen as the case study, and two finite element (FE) models are established in ABAQUS, with and without consideration of the interaction between the transmission towers and the transmission lines. The mode combination frequency is defined by considering the influence of the higher-order modes of the structure. Subsequently, wavelet transformation is performed to obtain the total effective energy input and the effective energy input rate corresponding to the mode combination frequency to further judge the critical angle of seismic incidence by comparing these two performance indexes under different seismic incidence angles. To validate this approach, finite element history analysis (FEHA) is imposed on both FE models to generate comparative data, and good agreement is found. The results demonstrate that the wavelet energy method can forecast the critical angle of seismic incidence of a transmission tower-line system with adequate accuracy, avoiding time-consuming and cumbersome computer analysis. The proposed approach can be used in future seismic design of transmission tower-line systems.

• Geomechanics and Engineering
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• v.27 no.6
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• pp.615-626
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• 2021

The main objective of this study is to present a fast and reliable approach to predict the swelling potential of clay-bearing rocks. Investigations showed that there is a good correlation between the swelling potential of a rock and its desire to absorb water due to its clay content which could be measured using the "Contact Angle" test as one of the most common ways to determine the wettability. In this test, the angle between a water drop and the flat rock surface on which it rests is measured. The present method is very fast and returns repeatable results and requires minimal sample preparation. Only having a saw-cut surface of a sample with any shape is all one needs to perform this test. The logic behind this approach is that the swelling potential of a rock is a function of its mineral content and molecular structure, which are not only distributed in the bulk of the sample but also reflected on its surface. Therefore, to evaluate swelling behavior, it is not necessary to wait for a sample to get wet all the way to its "internal structure" (which, due to the low permeability of clay-bearing rocks, is very slow and time-consuming). Instead, one can have a good sense of swelling potential by studying its surface. Parametric studies on the effect of moisture content, porosity, and surface roughness on the contact angle measurements showed that using a saw-cut oven-dried sample is a convenient way to evaluate the swelling potential by this method.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.541-555
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• 2000

Pultruded cross-sections are always thin-walled due to constraints in the manufacturing process. Thus, the buckling strength determines the overall strength of the member. The elastic buckling of pultruded angle sections subjected to direct compression is studied. The lateral-torsional buckling, very likely to appear in thin-walled cross-sections, is investigated. Plate theory is used to allow for cross-sectional distortion. Shear effects and bending-twisting coupling are accounted for in the analysis because of their significant role. A simplified approach for determining the maximum load of equal leg angle sections under compression is presented. The analytical results obtained in this study are compared to the manufacturer's design guidelines for compression members as well as with the design specifications for steel structural members. Experimental results are obtained for various length specimens of pultruded angle sections. The results presented in this paper correspond to actual pultruded equal leg angle sections being used in civil engineering structures.

• Honam Mathematical Journal
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• v.43 no.3
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• pp.385-402
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• 2021

The geometry of Poincaré disk itself is interpreted without any mapping to different spaces. Our approach might be one of the shortest and is intended for educational contribution.

• The Korean Journal of Pain
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• v.25 no.3
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• pp.168-172
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• 2012

Background: The aim of the study was to investigate the feasibility of fluoroscopy-guided anterior approach for suprascapular nerve block (SSNB). Methods: Twenty patients with chronic shoulder pain were included in the study. All of the nerve blocks were performed with patients in a supine position. Fluoroscopy was tilted medially to obtain the best view of the scapular notch (medial angle) and caudally to put the base of coracoid process and scapular spine on same line (caudal angle). SSNB was performed by introducing a 100-mm, 21-gauge needle to the scapular notch with tunnel view technique. Following negative aspiration, 1.0 ml of contrast was injected to confirm the scapular notch, and 1 % mepivacaine 2 ml was slowly injected. The success of SSNB was assessed by numerical rating scale (NRS) before and after the block. Results: The average NRS was decreased from $4.8{\pm}0.6$ to $0.6{\pm}0.5$ after the procedure (P < 0.05). The best view of the scapular notch was obtained in a medial angle of $15.1{\pm}2.2$ ($11-19^{\circ}$) and a caudal angle of $15.4{\pm}1.7^{\circ}$ ($12-18^{\circ}$). The average distance from the skin to the scapular notch was $5.8{\pm}0.6$ cm. None of the complications such as pneumothorax, intravascular injection, and hematoma formation was found except one case of partial brachial plexus block. Conclusions: SSNB by fluoroscopy-guided anterior approach is a feasible technique. The advantage of using a fluoroscopy resulted in an effective block with a small dose of local anesthetics by an accurate placement of a tip of needle in the scapular notch while avoiding pneumothorax.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.6
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• pp.458-465
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• 2013

Ship design engineering refers to the development and design of shipbuilding architectures in a drawing which reflects all relevant manufacturing processes. This paper provides analysis methods for model-information interfaces between hull structure design and outfitting design, and a technical application for manufacturing phases reflecting the pipe support pad and angle item automatically. The existing information procedure of pipe support pad and angle system processes information using drawing without model specification. Outfitting design team directly distributes drawings to the shop floor then manual-based marking and installation work are conducted refer to the distributed drawings. As a result, this process has become time consuming and causes problems in the productivity and quality improvement due to the rework caused by omitted or incorrect marking. The pipe support pad and angle marking is a method that automatically updates model information to hull structure design using sets of data that analyse the generated model in outfitting design processes. Therefore, this approach provides an efficient solution through design references without manual activities such as a reflection of hull structure design, cutting process, numerical control work, and dimension measurement and marking. The conversion of a method from the existing procedure based on manual marking to the reflective and automatic approach would have enabled to proceed installation work without manual activities for the measurement. Therefore, this research study proposes an efficient approach using pre-data analysis of model information interfaces between design and manufacturing phases to improve productivity during construction for shipbuilding.