• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.437-446
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• 2017

Objective: This study aims to draw an efficient UI design by comparing the usability of App drawer and single-layered home screens, which are smartphone home screens. Background: Because smartphone home screen is frequently used including the installation, deletion, and editing of APPs, it should be designed with easily controllable information structure. There is a need to seek a user-friendly UI by comparing the usability of App drawer and single-layered home screens, of which methods to search Apps are different. There is also a need to examine an efficient UI and the factors to improve from the user perspective. Method: This study targeted 30 Android OS and iOS users to evaluate the App drawer and single-layered home screens, of which UI structures are different. Each participant was instructed to carry out an App searching task and App deleting task, and the execution time and the number of errors were measured. After the tasks were completed, they evaluated satisfaction through a questionnaire survey. Results: In the App searching task with low task level, there was no difference in execution level between the App drawer and single-layered home screens. However, the single-layered home screen showed higher efficiency and accuracy in the App deleting task with high task level. As for the group difference according to use experience, there was no difference in satisfaction among Android OS users, but iOS user satisfaction with single-layered home screen with which they were familiar was higher. Conclusion: As for home screen usability, the single-layered home screen UI structure can be advantageous, as task level is higher. Repulsion was higher, when users, who had used easier UI, used complex UI in comparison with user satisfaction, when users familiar with complex UI used easier UI. A UI indicating the current status with clear label marking through a task flow chart-based analysis, and a UI in which a user can immediately recognize by exposing hidden functions to the first depth were revealed as things to improve. Application: The results of this study are expected to be used as reference data in designing smartphone home screens. Especially, when iOS users use Android OS, the results are presumed to contribute to the reduction of predicted barriers.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.229-232
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• 2001

This paper has analyzed an architecture of DSLAM, system software Architecture, an external interface of DSLAM module, Message transfer of each task. Also in this paper, message and structures between SNMP Agent and each internal board are defined, and from the defined messages and data structures, message processing between boards is designed and implemented

• Smart Structures and Systems
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• v.31 no.4
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• pp.335-349
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• 2023

Bridges constantly undergo deterioration and damage, the most common ones being concrete damage and exposed rebar. Periodic inspection of bridges to identify damages can aid in their quick remediation. Likewise, identifying components can provide context for damage assessment and help gauge a bridge's state of interaction with its surroundings. Current inspection techniques rely on manual site visits, which can be time-consuming and costly. More recently, robotic inspection assisted by autonomous data analytics based on Computer Vision (CV) and Artificial Intelligence (AI) has been viewed as a suitable alternative to manual inspection because of its efficiency and accuracy. To aid research in this avenue, this study performs a comparative assessment of different architectures, loss functions, and ensembling strategies for the autonomous segmentation of bridge components and damages. The experiments lead to several interesting discoveries. Nested Reg-UNet architecture is found to outperform five other state-of-the-art architectures in both damage and component segmentation tasks. The architecture is built by combining a Nested UNet style dense configuration with a pretrained RegNet encoder. In terms of the mean Intersection over Union (mIoU) metric, the Nested Reg-UNet architecture provides an improvement of 2.86% on the damage segmentation task and 1.66% on the component segmentation task compared to the state-of-the-art UNet architecture. Furthermore, it is demonstrated that incorporating the Lovasz-Softmax loss function to counter class imbalance can boost performance by 3.44% in the component segmentation task over the most employed alternative, weighted Cross Entropy (wCE). Finally, weighted softmax ensembling is found to be quite effective when used synchronously with the Nested Reg-UNet architecture by providing mIoU improvement of 0.74% in the component segmentation task and 1.14% in the damage segmentation task over a single-architecture baseline. Overall, the best mIoU of 92.50% for the component segmentation task and 84.19% for the damage segmentation task validate the feasibility of these techniques for autonomous bridge component and damage segmentation using RGB images.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.632-639
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• 2022

The objective of this study is to analyze the productivity, efficiency, and factors affecting the productivity of a spray task from an international airport project. The study is focused on the productivity analysis of the Subcontractor whose job was to supply and apply sprayed-applied fire-resistive material (SFRM) on steel members to achieve the necessary fire ratings on the building structures of the Hamad International Airport, Qatar. The study analyzed the productivity of the four sprayer teams who completed the task at three locations and three areas of the airport. The study found that the productivity of the individual team observed during the SFRM spray task was not only different but was also observed different when they worked at varying floor heights where different factors affecting productivity were predominant. The study found that the efficiency was lowest (47.32%) when the spray team had to work at second-floor heights and factors affecting productivity such as limited accessibility for material movement and lifting, site congestion, lack of continuity of operation due to priority areas and frequent re-handling of machines and tools were present. Besides, the factors such as adverse weather conditions and sub-trades interference affected productivity at all locations. The findings show that productivity depends on multiple factors and those factors need to be identified and addressed to improve productivity. The findings also show that the estimated efficiency was hard to achieve but possible since Team 4 had 97% efficiency on the first floor of the airport.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.743-746
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• 1996

A hybrid control scheme to regulate the force and position by dual arms is proposed, where two arms are treated as one arm in a kinematic viewpoint. Our approach is different from other hybrid control approaches which consider robot dynamics, in the sense that we employ a purely kinematic based approach for hybrid control, with regard to the nature of position-controlled industrial robots. The proposed scheme is applied to sawing task. In the sawing task, the trajectory of the saw grasped by dual arms is planned in an offline fashion. When the trajectory of the saw is planned to follow a line in a horizontal plane, 3 position parameters are to be controlled(i.e, two translational positions and one rotational position). And a certain level of contact force has to be controlled along the vertical direction(i.e., minus z-direction) not to loose the contact with the object to be sawn. Typical feature of sawing task is that the contact position where the force control is to be performed is continuously changing. Therefore, the kinematic mapping between the force controlled position and the joint actuators has to be updated continuously. The effectiveness of the proposed control scheme is experimentally demonstrated. The proposed hybrid control scheme can be applied to arbitrary dual arm systems, regardless of their kinematic structure and the number of actuated joints.

• Structural Engineering and Mechanics
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• v.12 no.1
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• pp.101-118
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• 2001

The reliable prediction of elastic vibrations of wetted complex structures, as ships, tanks, offshore structures, propulsion components etc. represent a theoretical and numerical demanding task due to fluid-structure interaction. The paper presented is addressed to the vibration analysis by a combined FE-BE-procedure based on the added mass concept utilizing a direct boundary integral formulation of the potential fluid problem in interior and exterior domains. The discretization is realized by boundary element collocation method using conventional as well as infinite boundary element formulation with analytical integration scheme. Particular attention is devoted to modelling of interior problems with both several separate or communicating fluid domains as well as thin-walled structures wetted on both sides. To deal with this specific kind of interaction problems so-called "virtual" boundary elements in areas of cut outs are placed to satisfy the kinematical conditions in partial connected fluid domains existing in realistic tank systems. Numerical results of various theoretical and practical examples demonstrate the performance of the BE-methodology presented.

• Smart Structures and Systems
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• v.23 no.2
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• pp.123-139
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• 2019

Impact forces induced by external object collisions can cause serious damages to civil engineering structures. While accurate and prompt identification of such impact forces is a critical task in structural health monitoring, it is not readily feasible for civil structures because the force measurement is extremely challenging and the force location is unpredictable for full-scale field structures. This study proposes a novel approach for identification of impact force including its location and time history using a small number of multi-metric observations. The method combines an augmented Kalman filter (AKF) and Genetic algorithm for accurate identification of impact force. The location of impact force is statistically determined in the way to minimize the AKF response estimate error at measured locations and then time history of the impact force is accurately constructed by optimizing the error co-variances of AKF using Genetic algorithm. The efficacy of proposed approach is numerically demonstrated using a truss and a plate model considering the presence of modelling error and measurement noises.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1183-1210
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• 2016

Viscoelastic sandwich structures (VSSs) are widely used in mechanical equipment, but in the service process, they always suffer from aging which affect the whole performance of equipment. Therefore, aging state recognition of VSSs is significant to monitor structural state and ensure the reliability of equipment. However, non-stationary vibration response signals and weak state change characteristics make this task challenging. This paper proposes a novel method for this task based on adaptive second generation wavelet packet transform (ASGWPT) and multiwavelet support vector machine (MWSVM). For obtaining sensitive feature parameters to different structural aging states, the ASGWPT, its wavelet function can adaptively match the frequency spectrum characteristics of inspected vibration response signal, is developed to process the vibration response signals for energy feature extraction. With the aim to improve the classification performance of SVM, based on the kernel method of SVM and multiwavelet theory, multiwavelet kernel functions are constructed, and then MWSVM is developed to classify the different aging states. In order to demonstrate the effectiveness of the proposed method, different aging states of a VSS are created through the hot oxygen accelerated aging of viscoelastic material. The application results show that the proposed method can accurately and automatically recognize the different structural aging states and act as a promising approach to aging state recognition of VSSs. Furthermore, the capability of ASGWPT in processing the vibration response signals for feature extraction is validated by the comparisons with conventional second generation wavelet packet transform, and the performance of MWSVM in classifying the structural aging states is validated by the comparisons with traditional wavelet support vector machine.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.113-119
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• 2004

A steel plated is typically composed of plate panels. The overall failure of the structure is certainly affected and can be governed by the bulking and plastic collapse of these individual members In the ultimate limit state design. therefore. a primary task is to accurately calculate the budding and plastic collapse strength of such structural members. Structural elements making up steel palated structures do not work separately. resulting in high degree of redundancy and complexity in contrast to those of steel framed structures. To enable the behavior of such structures to be analyzed, simplifications or idealizations must essentially be made considering the accuracy need and degree of complexity of the analysis to be used Generally the more complex the analysis the greater is the accuracy that may be obtained. The aim of this study is the investigation of the effect of the tripping behaviour including section characteristic for a plate under uniaxial compression.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.4
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• pp.33-39
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• 2014

To establish the reliability of a packaging structures, adhesion testing of key interfaces is a critical task. Due to the material mismatch, the interface may be prone to delamination failure due to conditions during the manufacturing of the product or just from the day-to-day use. To assess the reliability of the interface adhesion strength testing can be performed during the design phase of the product. One test method of interest is the four-point bending (4PB) adhesion strength test method. This test method has been implemented in a variety of situations to evaluate the adhesion strength of interfaces in bimaterial structures to the interfaces within thin film multilayer stacks. This article presents a review of the 4PB adhesion strength testing method and key implementations of the technique in regards to semiconductor packaging.