• Advances in nano research
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• 제12권2호
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• pp.139-150
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• 2022

This paper presents sets of explicit analytical equations that compute the static displacements of nanobeams by adopting the nonlocal elasticity theory of Eringen within the framework of Euler Bernoulli and Timoshenko beam theories. Castigliano's theorem is applied to an equivalent Virtual Local Beam (VLB) made up of linear elastic material to compute the displacements. The first derivative of the complementary energy of the VLB with respect to a virtual point load provides displacements. The displacements of the VLB are assumed equal to those of the nonlocal beam if nonlocal effects are superposed as additional stress resultants on the VLB. The illustrative equations of displacements are relevant to a few types of loadings combined with a few common boundary conditions. Several equations of displacements, thus derived, matched precisely in similar cases with the equations obtained by other analytical methods found in the literature. Furthermore, magnitudes of maximum displacements are also in excellent agreement with those computed by other numerical methods. These validated the superposition of nonlocal effects on the VLB and the accuracy of the derived equations.

• 국제초고층학회논문집
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• 제11권4호
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• pp.265-276
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• 2022

Double-Skin Facades (DSF) on tall buildings are becoming increasingly common in urban environments due to their ability to provide architectural merit, passive design, acoustic control and even improved structural efficiency. This study aims to understand the effects of porous DSF on the aerodynamic characteristics of tall buildings using wind tunnel tests. High Frequency Force Balance and pressure tests were performed on the CAARC standard tall building model with a variable porous DSF on the windward face. The introduction of a porous DSF did not adversely affect the overall mean forces and moments experienced by the building, with few differences compared to the standard tall building model. There was also minimal variation between the results for the three porosities tested: 50%, 65% and 80%. The presence of a full-height porous DSF was shown to effectively reduce the mean and fluctuating wind pressure on the side face of the building by about 10%, and a porous DSF over the lower half height of the building was almost as effective. This indicates that the porous DSF could be used to reduce the design load on cladding and fixtures on the side faces of tall buildings, where most damage to facades typically occurs.

• Wind and Structures
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• 제37권3호
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• pp.179-189
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• 2023

Multiple studies conducted in the past evaluated the conductor response under one tornado wind field, while the performance of transmission lines under different tornado wind fields still remains unknown. Thus, the objective of this paper is to estimate the variation in the conductor's critical longitudinal and transverse reactions under different tornado wind fields, as well as providing the corresponding critical tornado configurations. The considered full-scale tornadoes are the Spencer, South Dakota, 1998, the Stockton, Kansas, 2005 and the Goshen County, Wyoming, 2009. Computational Fluid Dynamics (CFD) simulations were previously conducted to develop these wind fields. All tornadoes have been rescaled to have a common velocity matching the upper limit of the F2 Fujita scale. Eight conductor systems, each including six spans, are considered in this paper. For each conductor, parametric studies are conducted by varying the location of the three tornado wind fields relative to the tower of interest, therefore the peak reactions associated with each tornado are determined. A semi-analytical closed-form solution, previously developed and validated, is used to calculate the reactions. The study conducted in this paper can be divided into two parts: In the first part, a parametric study considering a wide range of tornado locations is conducted. In the second part, the parametric study focuses on the tornado location leading to the critical tangential velocity on the tower. Based on this extensive parametric study, a critical tornado defined as the Design Tornado and its critical locations, tornado distance R = 125 m, tornado angle 𝜃 = 15° and 30°, are recommended for design purposes.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.187-197
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• 2023

Today's world is experiencing rapid technological advancement like never before. The ever-changing technology space has overwhelmed citizens with a substantial load of information, which has made it difficult for them to keep up with the technology awareness. This review paper is written to provide information about the Internet of Things in a way that technical along with nontechnical individuals can understand the definition, historical evolution, components, and scope of IoT technology. Relevant literature published between January 2009 and February 2023 was included in this paper. The applications of the Internet of Things in healthcare have been a special focus of this paper as IoT has massive potential in this field and healthcare professionals often face significant issues in keeping their technology knowledge up to date. Moreover, some of the most common issues associated with IoT introduction in healthcare are also discussed in the paper along with some suitable recommendations. Although, IoT can significantly transform our lives and can introduce convenience and efficiency, particularly in the healthcare sector. However, its adoption in healthcare is still a major task due to various challenges presented by the health workforce. Thus, in-depth empirical research is suggested to assist the IoT technology transition.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.98-99
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• 2021

The number of fires in the Korean distribution warehouse increased by about 350 from 1,070 in 2014 to 1,416 in 2020. In addition, the fire load increases with the scale of the distribution warehouse, and even if the automatic sprinkler operates, there is a limit to the direct intrusion of the water source into the ignition source, and the detector is often installed on a high ceiling. The sensing time is often delayed. In order to improve the fire safety of such distribution warehouses, the US NFPA stipulates in detail the contents related to the facility, such as sprinkler water discharge standards, rack-type warehouse installation height restrictions, and regulations on collection and equipment. However, in Japan, the goods loaded inside the distribution warehouse are not classified in detail, and it is considered that the fire safety for the distribution warehouse is low due to the relaxation regulations of the fire prevention section. Therefore, in this study, common problems are classified into material, spatial, and safety management characteristics through the cases of distribution warehouse fires that occurred in Korea and abroad, and the problems related to distribution warehouses in Korea and abroad are compared and analyzed. And present basic materials for improving the life safety standards of future distribution warehouse facilities.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7213-7218
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• 2014

Background: Egypt has one of the highest prevalences of hepatitis C virus (HCV) infection worldwide. Although the IL28B gene polymorphism has been shown to modify the course of chronic HCV infection, this has not been properly assessed in the Egyptian population. Materials and Methods: The IL28B rs12979860 single nucleotide polymorphism (SNP) was therefore examined in 256 HCV-infected Egyptian patients (group II) at different stages of disease progression and in 48 healthy volunteers (group I). Group II was subdivided into GII-A (chronic hepatitis patients, n=119), GII-B (post hepatitis cirrhosis, n=66) and GII-C (HCC on top of cirrhosis, n=71). Results: The C/T genotype was the commonest in all groups. It was more frequent in GI (52%) than in GII (48%). There was no significant difference in the frequency of C/T and C/C or T/T genotypes between groups and subgroups (p=0.82). Within the subgroups; the C/C genotype was more common in GII-B while C/T and T/T genotypes were more common in GII-C, though with no significant difference (p=0.59 and p=0.80). There was no significant association between IL28B rs12979860 SNP and viral load, ALT, AFP level, METAVIR scores for necro-inflammation and fibrosis, and Child-Pugh classification. Conclusions: 1) IL28Brs12979860 C/T genotype is the commonest genotype in HCV-associated CH and HCC in Egypt. 2) IL28Brs12979860 polymorphisms are not associated with disease progression or aggression (histological staging, severity of fibrosis in CH or the incidence of post-HCV HCC). 3) Differences in IL28Brs12979860 genotypes could be a consequence of environmental or ethnic variation.

• 영재교육연구
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• 제19권2호
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• pp.353-380
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• 2009

영재교육의 시행 확대에 따라 정보과학영재교육에 대한 관심이 증가하고 있으나, 수학 과학 분야의 영재교육에 비하여 선발 및 교육내용에 대한 연구결과물이 부족한 상황이다. 또한, 정보과학영재교육을 시행함에 있어 알고리즘 교육영역은 가장 핵심적인 분야 중 하나이나, 알고리즘 교육을 초등정보과학영재의 수준에 맞추어 교육한다는 것은 어려운 일이다. 이와 같은 이유로 인하여 정보과학영재교육 분야 중 가장 핵심적인 영역인 알고리즘 교육내용에 대한 기존의 연구는 매우 미비한 실정이다. 이에 본 논문에서는 다음과 같은 절차에 따른 연구를 시행하였다. 첫째, 정보과학영재의 정의 및 특성을 분석하고 이에 따른 정보과학영재교육의 목표 및 교육내용과 알고리즘 교육내용을 분석하였다. 둘째, 분석 내용을 기반으로 초등정보과학영재를 위한 알고리즘 교육내용 개발 기준과 활동지 개발 기준을 제안하였다. 셋째, 본 논문에서 제안한 알고리즘 교육내용과 활동지 개발의 타당성을 검증하기 위하여 경인지역의 초등정보과학영재교육 전문가 그룹을 활용한 델파이 분석을 시행하였다.

• 한국환경복원기술학회지
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• 제23권4호
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• pp.69-84
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• 2020

Up to date, the majority research on the major landscape elements in organic farming has been mainly focused on the practice of seeking efficiency. The problem is that this type of study contributes to polluting the agricultural environment and damaging the ecological circulation system. As an alternative, there is a growing body of research on organic farming, but it is not widely applied that research on how to manage the landscape considering the scenic characteristics of farming villages practicing organic farming. Hence, in this paper we utilized landscape adjectives as a way to enhance the objectivity of the organic agricultural complex landscape assessment. More specifically, not only this study used a landscape image of an organic agricultural complex to identify a landscape adjective suitable for the landscape elements but also this study confirmed the suitability of landscape adjectives comparing to the opinions of experts and the public. To carry out, this study performed the experts survey which is composed of 12 major landscape elements, including rice paddies and fields, monoculture and diverse crops, dirt roads, windbreak trees, accent planting, dum-bung(small pond), natural small river, natural waterways, plastic film houses, one-storied houses, and pavilion. As a result of deriving the landscape adjectives from the main landscape elements, there were nine landscape adjectives that were consistent with experts and the public, including "clear" and "Artless" for rice paddies and fields, while the mismatched landscape adjectives were 'traditional'. The accent planting was a combination of landscape adjectives such as 'natural' and 'clear', while the windbreak trees was a consensus of all landscape adjectives. Only two adjectives, 'friendly' and 'wild', agreed on the dirt load, nine dum-bung(small pond), ten natural small river, nine duckery, eight one-storied houses, 10 pavilion, eight monoculture and diverse crops, and three natural waterways. The most common landscape adjectives were windbreak trees, pavilions, and natural small river, all 10 landscape adjectives. However, it is considered that only three of the 10 landscape types on the dirt road and the natural number are matched. Thus, additional management measures will be needed. In addition, it was analyzed that the most common landscape adjectives were "Artless" and "friendly" 13 times. The landscape adjectives of the organic farming complex responded by experts were analyzed to be suitable for natural, clear, zingy, silent, traditional, artless, friendly, wild and Leisurely, and consistent with the general public's opinion.

• Geomechanics and Engineering
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• 제8권6호
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• pp.859-872
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• 2015

Pebble matrix filtration (PMF) is a water treatment technology that can remove suspended solids in highly turbid surface water during heavy storms. PMF typically uses sand and natural pebbles as filter media. Hand-made clay pebbles (balls) can be used as alternatives to natural pebbles in PMF treatment plants, where natural pebbles are not readily available. Since the high turbidity is a seasonal problem that occurs during heavy rains, the use of newly developed composite clay balls instead of pure clay balls have the advantage of removing other pollutants such as natural organic matter (NOM) during other times. Only the strength properties of composite clay balls are described here as the pollutant removal is beyond the scope of this paper. These new composite clay balls must be able to withstand dead and live loads under dry and saturated conditions in a filter assembly. Absence of a standard ball preparation process and expected strength properties of composite clay balls were the main reasons behind the present study. Five different raw materials from industry wastes: Red Mud (RM), Water Treatment Alum Sludge (S), Shredded Paper (SP), Saw Dust (SD), and Sugar Mulch (SM) were added to common clay brick mix (BM) in different proportions. In an effort to minimize costs, in this study clay balls were fired to $1100^{\circ}C$ at a local brick factory together with their bricks. A comprehensive experimental program was performed to evaluate crushing strength of composite hand-made clay balls, using uniaxial compression test to establish the best material combination on the basis of strength properties for designing sustainable filter media for water treatment plants. Performance at both construction and operating stages were considered by analyzing both strength properties under fully dry conditions and strength degradation after saturation in a water bath. The BM-75% as the main component produced optimum combination in terms of workability and strength. With the material combination of BM-75% and additives-25%, the use of Red Mud and water treatment sludge as additives produced the highest and lowest strength of composite clay balls, with a failure load of 5.4 kN and 1.4 kN respectively. However, this lower value of 1.4 kN is much higher than the effective load on each clay ball of 0.04 kN in a typical filter assembly (safety factor of 35), therefore, can still be used as a suitable filter material for enhanced pollutant removal.

• Earthquakes and Structures
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• 제14권4호
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• pp.323-336
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• 2018

Machine foundations with impact loads are common powerful sources of industrial vibrations. These foundations are generally transferring vertical dynamic loads to the soil and generate ground vibrations which may harmfully affect the surrounding structures or buildings. Dynamic effects range from severe trouble of working conditions for some sensitive instruments or devices to visible structural damage. This work includes an experimental study on the behavior of dry dense sand under the action of a single impulsive load. The objective of this research is to predict the dry sand response under impact loads. Emphasis will be made on attenuation of waves induced by impact loads through the soil. The research also includes studying the effect of footing embedment, and footing area on the soil behavior and its dynamic response. Different falling masses from different heights were conducted using the falling weight deflectometer (FWD) to provide the single pulse energy. The responses of different soils were evaluated at different locations (vertically below the impact plate and horizontally away from it). These responses include; displacements, velocities, and accelerations that are developed due to the impact acting at top and different depths within the soil using the falling weight deflectometer (FWD) and accelerometers (ARH-500A Waterproof, and Low capacity Acceleration Transducer) that are embedded in the soil in addition to soil pressure gauges. It was concluded that increasing the footing embedment depth results in increase in the amplitude of the force-time history by about 10-30% due to increase in the degree of confinement. This is accompanied by a decrease in the displacement response of the soil by about 40-50% due to increase in the overburden pressure when the embedment depth increased which leads to increasing the stiffness of sandy soil. There is also increase in the natural frequency of the soil-foundation system by about 20-45%. For surface foundation, the foundation is free to oscillate in vertical, horizontal and rocking modes. But, when embedding a footing, the surrounding soil restricts oscillation due to confinement which leads to increasing the natural frequency. Moreover, the soil density increases with depth because of compaction, which makes the soil behave as a solid medium. Increasing the footing embedment depth results in an increase in the damping ratio by about 50-150% due to the increase of soil density as D/B increases, hence the soil tends to behave as a solid medium which activates both viscous and strain damping.