• Computers and Concrete
• /
• v.24 no.2
• /
• pp.151-158
• /
• 2019

The sustainable development principle of replacing natural resources with renewable material is an important research topic. In this study, waste LCD (liquid crystal display) glass powder was used to replace cement (0%, 10%, 20% and 30%) through a volumetric method using three water-binder ratios (0.47, 0.59, and 0.71) to make cement mortar. The compressive strength was tested at the ages of 7, 28, 56 and 91 days. The test results show that the compressive strength increases with age but decreases as the water-binder ratio increases. The compressive strength slightly decreases with an increase in the replacement of LCD glass powder at a curing age of 7 days. However, at a curing age of 91 days, the compressive strength is slightly greater than that for the control group (glass powder is 0%). When the water-binder ratios are 0.47, 0.59 and 0.71, the compressive strength of the various replacements increases by 1.38-1.61 times, 1.56-1.80 times and 1.45-2.20 times, respectively, during the aging process from day 7 to day 91. Furthermore, a prediction model of the compressive strength of a cement mortar with waste LCD glass powder was deduced in this study. According to the comparison between the prediction analysis values and test results, the MAPE (mean absolute percentage error) values of the compressive strength are between 2.79% and 5.29%, and less than 10%. Thus, the analytical model established in this study has a good forecasting accuracy. Therefore, the proposed model can be used as a reliable tool for assessing the design strength of cement mortar from early age test results.

• Structural Engineering and Mechanics
• /
• v.71 no.6
• /
• pp.603-625
• /
• 2019

Main cable configurations under final dead load and in the unloaded state and critical construction parameters (e.g. unstrained cable length, unstrained hanger lengths, and pre-offsets for tower saddles and splay saddles) are the core considerations in the design and construction control of a suspension bridge. For the purpose of accurate calculations, it is necessary to take into account the effects of cable strands over the anchor spans, arc-shaped saddle top, and tower top pre-uplift. In this paper, a method for calculating the cable configuration under final dead load over a main span, two side spans, and two anchor spans, coordinates of tangent points, and unstrained cable length are firstly developed using conditions for mechanical equilibrium and geometric relationships. Hanger tensile forces and unstrained hanger lengths are calculated by iteratively solving the equations governing hanger tensile forces and the cable configuration, which gives careful consideration to the effect of hanger weight. Next, equations for calculating the cable configuration in the unloaded state and pre-offsets of saddles are derived from the cable configuration under final dead load and the conditions for unstrained cable length to be conserved. The equations for the main span, two side spans and two anchor spans are then solved simultaneously. In the proposed methods, coupled nonlinear equations are solved by turning them into an unconstrained optimization problem, making the procedure simplified. The feasibility and validity of the proposed methods are demonstrated through a numerical example.

• Journal of Research and Publication Ethics
• /
• v.2 no.2
• /
• pp.21-24
• /
• 2021

Purpose: This paper aims to evaluate and reinstate preventative guidelines necessary for a sound academic journal (or academic conference) for the articles published by KODISA and its branch journals. As questionable or predatory academic journals and academic conferences are rapidly increasing, preemptively establishing preventative standards have become essential to obviate questionable academic activities. Research design, data and methodology: This is an analytical study that explores and examines research, publication ethics, and misconducts. For this purpose, research ethics related data in overseas and domestic academic journals have been examined and analyzed. Results: The issues identified from this research are as follows: enhancing the expertise of editor-inchief (no concurrent jobs for major and non-major area); clarifying the index; complying with the review policy (The review policy should be publicly announced); complying with anonymous review process; complying with 3 peer-review policy, complying with the publication policy as per field of study; avoiding conference hosting at holiday resorts unless unavoidable; complying with the planned programs and cancelling events if not feasible; following proper review standards and management for all journals, including the journals publishing large number of articles (all materials should be prepared in case explanatory data is required); complying with the marketing policy standards; complying with the impact factor; excluding personal solicitation; and complying with the general policy. Conclusions: Questionable and predatory academic activities by academic organizations and journals will continue, and it is the responsibility of the individual scholars to identify and reject these types of dubious academic activities. This study provides standards to prevent the possibility of questionable academic activities that have been conducted in the past. The analysis and findings will strengthen the continued efforts of KODISA as it strives to be a transparent, ethical, and professional academic association, and the association will continue to foster an academic environment that is well-respected by scholars and practitioners throughout the world.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.34 no.9
• /
• pp.31-42
• /
• 2018

With the rapid progress of urbanization today, communities among members of society have collapsed. For dealing with the collapse of communities, special laws regarding urban regeneration revitalization and support were enforced and each local government founded community centers to revitalize urban village communities. These community centers were built to play a pivotal role in communities, but they have difficulties managing and supervising. Therefore, this study aims to provide basic data for community center planning and revitalization by examining and analyzing the present state of community center spaces for creation of communities among residents and the present state of use so the existing purpose of establishment as a base space of village community revitalization can be achieved in the future. For this study, first, in the literature review, the concepts of village community and community center were established, based on a theoretical consideration, and the need of research was identified through consideration of preceding studies. Second, in relation to the present state of use, the present state of community center spaces, programs, management and supervision, locations and populations was investigated and analyzed, and community center users' basic characteristics, satisfaction and consciousness of community centers were examined and analyzed. Based on this method and analysis, this study is focused on providing basic data for community center revitalization and planning.

• Journal of the Architectural Institute of Korea Planning & Design
• /
• v.35 no.3
• /
• pp.91-102
• /
• 2019

This study explores the causes and processes of morphological transformation of apartment complexes in Busan. All apartment complexes built until the year 2016 were selected for statistical analysis, drawing/map examination, field observation, selected expert interviews based on 6 periodical groups: Period I(~1990), Period II(1991~1995), Period III(1996~2000), Period IV(2001~2005), Period V(2006~2010), and Period VI(2011~2016). The research argues for three 'arrangement' types, P1U, L1U and P2U, which have dominated the whole periods occupying 88% of the total 260 complexes. The switch of the leading type represents for morphological transformation of apartment complexes. Four aspects, density(F.A.R.), height(maximum number of floors), deformed-building-type ratio, and building-orientation, have affected the change of 'arrangement' types. Density was the major cause of the arrangement-type switch, from P1U to L1U, on Period II(1991~1995). The morphological change, from type L1U to P2U, on Period V(2006~2010) was caused by height and orientation, and is correlated with the increased number of deformed-type buildings. The first phase morphological change on Period II(1991~1995) was resulted by the supply side of apartment. However, the second phase transformation on Period V(2006~2010) had gone through the complex process including reflection of consumers' demands. The significance of research is to reveal the morphological transformation process of apartment complexes through analytical investigation of the entire apartment data in Busan. The result shows that the major change of urban paysage started to occur from Period V(2006~2010), and the superficial evaluation on apartment 'being monotonous and repetitive' may not be proper at least from the perspective of town plan.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.9
• /
• pp.3-10
• /
• 2018

While computer environments have been dramatically developed in recent years, as the building structures become larger, the structural analysis models are also becoming more complex. So there is still a need to model one shear wall with one finite element. From the viewpoint of the concept of FEA, if one shear wall is modeled by one finite element, the result of analysis is not likely accurate. Shear wall may be modelled with various finite elements. Among them, considering the displacement compatibility condition with the beam element connected to the shear wall, plane stress element with in-plane rotational stiffness is preferred. Therefore, in order to analyze one shear wall with one finite element accurately, it is necessary to evaluate finite elements developed for the shear wall analysis and to develop various plane stress elements with rotational stiffness continuously. According to the above mentioned need, in this study, the theory about a plane stress element using hierarchical interpolation equation is reviewed and stiffness matrix is derived. And then, a computer program using this theory is developed. Developed computer program is used for numerical experiments to evaluate the analysis results using commercial programs such as SAP2000, ETABS, PERFORM-3D and MIDAS. Finally, the deflection equation of a cantilever beam with narrow rectangular section and bent by an end load P is derived according to the elasticity theory, and it is used to for comparison with theoretical solution.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.15 no.7
• /
• pp.2513-2530
• /
• 2021

With the fast development of information and communication technologies, video streaming services and applications are increasing rapidly. However, the network condition is volatile. In order to provide users with better quality of service, it is necessary to develop an accurate and low-complexity model for Quality of Experience (QoE) prediction of time-varying video. Memory effects refer to the psychological influence factor of historical experience, which can be taken into account to improve the accuracy of QoE evaluation. In this paper, we design subjective experiments to explore the impact of Short-Term Memory (STM) on QoE. The experimental results show that the user's real-time QoE is influenced by the duration of previous viewing experience and the expectations generated by STM. Furthermore, we propose analytical models to determine the relationship between intrinsic video quality, expectation and real-time QoE. The proposed models have better performance for real-time QoE prediction when the video is transmitted in a fluctuate network. The models are capable of providing more accurate guidance for improving the quality of video streaming services.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.2
• /
• pp.45-53
• /
• 2011

Soil nailing method was often designed by the slope stability analysis based on limit equilibrium. However, in the case of shorten length of nails, although the calculated factor of safety is within the design factor of safety, the horizontal displacement of soil nailed walls occurred above the allowable limit. In this study, relationship between the load and factor of safety, and relationship between the load and displacement ratio based on the test results were analysed. From the analysed results, the relationship between factor of safety and displacement ratio was estimated. For the mobilized horizontal displacement of the walls within the serviceability limit corresponding to the displacement of less than 0.3% displacement ratio, the calculated factor of safety by limit equilibrium analysis had to satisfy above 1.35. Also, although the minimum factor of safety is estimated above 1.35, the maximum horizontal displacement is often mobilized above 0.3% of excavation height. Therefore, it is necessary to perform the numerical analysis of soil nailed walls in the case of low shear strength or high excavation.

• The Journal of Churna Manual Medicine for Spine and Nerves
• /
• v.16 no.2
• /
• pp.97-105
• /
• 2021

Objectives This study is aimed to evaluate cost-effectiveness of treatment of Korean Medicine for whiplash associated disorders (WAD) and to suggest the direction of future research. Methods We searched papers in Pubmed database to use some keywords indicating whiplash injury syndrome, treatment of Korean Medicine and cost-effectiveness. After searching, appropriate papers were selected depending on the exclusion criteria. The selected papers were analyzed in the sections of author, publication year, intervention and control groups, outcome measurement, the list including in the cost, cost-effectiveness, cost-utility and study design. Results Four studies about effect of Korean medicine and 3 studies about economic evaluation were finally included. Acupuncture was effective for balance disorder and neck pain. Economic evaluation studies used analytical decision model or cost-consequence analysis. Cost-effectiveness analysis using visual analog scale and cost-utility analysis using quality adjusted life years were performed. Initiating timing of proper management affected the consequence of treatments. Direct and indirect medical costs including supportive devices, and non-medical costs such as litigation were considered. Conclusions We conclude that studies haven't been conducted so far to evaluate the cost-effectiveness of Korean Medicine in whiplash injury syndrome. Thus, future studies are needed in this section.

• Journal of Korean Physical Therapy Science
• /
• v.28 no.3
• /
• pp.11-29
• /
• 2021

Background: The purpose of this study is to investigate the effects of virtual reality on gait, balance, and upper extremity functions compared to other independent variables or no variables. Additionally, the possibility of virtual reality for stroke patients was discussed. Design: Meta-analysis. Methods: The search for this study was a search term that combined stroke, virtual reality, and training, and the electronic search was conducted through EMBASE, MEDLINE, and Cochrane Library. As a result of the search, 21 studies satisfying the selection criteria of the target study were confirmed as the final analysis target. This study consisted of 21 randomized experimental studies and 21 randomized controlled trials, and the total number of participants was 642. [Experimental group (n=314), control group (n=328); total 642]. As a result of the study, upper extremity function was assessed using a box and block test, a modified Ashworth scale, and a scale including range of motion. The balance was evaluated by the berg balance scale. Gait was a Timed Up and Go test (TUG), stride length, and gait function. Scales including a walking rate scale were evaluated. The effect size for the intervention of the analytical study was meta-analyzed with the RevMan 5.3.3 program of the Cochrane library. Results: The results of the study showed that the function of walking was statistically significant. Balance showed statistically significant results. The upper extremity function showed no statistically significant results. Conclusion: Through this rehabilitation treatment by applying virtual reality environment to the rehabilitation of stroke patients in the future can be proposed as an effective intervention method for the balance and gait function of stroke patients.