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        검색결과 455

        1.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Although concerns about overheating of the franchise industry's market structure continue to be raised, there are few studies that analyze the market structure of the franchise industry and suggest practical use. Most existing studies mainly analyze the market structure of other industries using industrial concentration(HHI) as an indicator of market competition intensity from the perspective of industrial organization theory. This study seeks to present a market structure analysis method that is different from existing methods. Considering practical application, this study presented a method to analyze the market structure that combines industry concentration(HHI) analysis and matrix analysis of the franchise industry. First, the industry concentration(HHI) and operating profit ratio(SMR) of 15 major industries in the franchise industry were analyzed in a time series manner (2014-2019). Second, using industrial concentration and operating profit ratio(SMR) as two variables on the x-axis and y-axis, a two-stage matrix analysis was used to understand the market structure characteristics of 15 industries at a glance. Third, a method of utilizing the matrix analysis results for practical decision-making was presented.
        4,500원
        2.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Vertical takeoff and landing (VTOL) is a core feature of unmanned aerial vehicles (UAVs), which are commonly referred to as drones. In emerging smart logistics, drones are expected to play an increasingly important role as mobile platforms. Therefore, research on last-mile delivery using drones is on the rise. There is a growing trend toward providing drone delivery services, particularly among retailers that handle small and lightweight items. However, there is still a lack of research on a structural definition of the VTOL drone flight model for multi-point delivery service. This paper describes a VTOL drone flight route structure for a multi-drone delivery service using rotary-wing type VTOL drones. First, we briefly explore the factors to be considered when providing drone delivery services. Second, a VTOL drone flight route model is introduced using the idea of the nested graph. Based on the proposed model, we describe various time-related attributes for delivery services using drones and present corresponding calculation methods. Additionally, as an application of the drone route model and the time attributes, we comprehensively describe a simple example of the multi-drone delivery for first-come-first-served (FCFS) services.
        4,600원
        3.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: As the number of households raising companion dogs increases, the pet genetic analysis market also continues to grow. However, most studies have focused on specific purposes or native breeds. This study aimed to collect genomic data through single nucleotide polymorphism (SNP) chip analysis of companion dogs in South Korea and perform genetic diversity analysis and SNP annotation. Methods: We collected samples from 95 dogs belonging to 26 breeds, including mixed breeds, in South Korea. The SNP genotypes were obtained for each sample using an Axiom™ Canine HD Array. Quality control (QC) was performed to enhance the accuracy of the analysis. A genetic diversity analysis was performed for each SNP. Results: QC initially selected SNPs, and after excluding non-diverse ones, 621,672 SNPs were identified. Genetic diversity analysis revealed minor allele frequencies, polymorphism information content, expected heterozygosity, and observed heterozygosity values of 0.220, 0.244, 0.301, and 0.261, respectively. The SNP annotation indicated that most variations had an uncertain or minimal impact on gene function. However, approximately 16,000 non-synonymous SNPs (nsSNPs) have been found to significantly alter gene function or affect exons by changing translated amino acids. Conclusions: This study obtained data on SNP genetic diversity and functional SNPs in companion dogs raised in South Korea. The results suggest that establishing an SNP set for individual identification could enable a gene-based registration system. Furthermore, identifying and researching nsSNPs related to behavior and diseases could improve dog care and prevent abandonment.
        4,000원
        4.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        강원도 가리왕산, 발왕산, 방태산, 함백산의 아고산대에서 출현하는 사스래나무군락 25개 조사구를 대상으로 식생조 사를 실시하고 분석하였다. TWINSPAN 및 DCA 분석 결과, 사스래나무-신갈나무군락(GroupⅠ), 사스래나무-당단풍 나무군락(GroupⅡ), 사스래나무군락(GroupⅢ)의 총 3개 군락으로 분류되었다. 사스래나무-신갈나무군락(GroupⅠ)은 해발 1,082~1,192m 방태산 등산로 주변에 위치하고, 사스래나무-당단풍나무군락(GroupⅡ)은 해발 1,230~1,373m 방 태산, 가리왕산, 함백산의 능선과 사면에 위치한다. 사스래나무-신갈나무군락과 사스래나무-당단풍나무군락은 현재 교목층에 사스래나무가 우점하고 있으나 장기적으로는 경쟁 관계인 신갈나무가 우점할 것으로 예상된다. 사스래나무군 락(GroupⅢ)은 해발 1,428~1,464m 함백산과 발왕산 정상부 전석지에 위치한다. 현재 사스래나무 세력이 매우 우세하 고 차세대 형성도 활발하여 앞으로도 사스래나무가 우점할 것으로 예상된다. 사스래나무군락은 일반적으로 해발 1,000m 이상에서 출현하며, 해발고도가 높을수록 사스래나무의 세력이 우세한 것으로 나타났다. 토양 분석 결과, 설악산 대청봉 및 지리산 반야봉 아고산대 지역과 비슷한 양상을 보였다. 군락별 종다양도는 1.210~1.293, 균재도는 0.698~0.795, 우점도는 0.208~0.302로 나타났다.
        4,500원
        5.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper introduces a study on measuring the 3D vibration displacement of plate structure using Digital Image Correlation (DIC) applied to stereo digital continuous camera images. The proposed method is a non-contact 3D displacement measurement method that does not require physical sensors to be attached to the structure, and it has the advantage of simultaneously measuring dynamic displacements at multiple points on the structure. Theoretically, multiple cameras can be used, but in this study, two cameras were used to capture continuous images of the vibrating structure, and the image coordinates of multiple tracking points at arbitrary positions on the structure were measured using correlation matching. Using these image coordinates as input data, the dynamic 3D positions were calculated through Space intersection, successfully determining the 3D dynamic displacements. The measured dynamic displacements were validated for accuracy by comparing them with values measured by laser displacement sensors. And frequencies of measured data were validated by comparing with computational modal analysis by Finite Element Model (FEM).
        4,000원
        6.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        유체-구조물-지반 상호작용을 고려한 액체저장탱크의 유한요소 모형을 제시하고, 비선형 지진응답 해석기법을 정식화한다. 탱크 구조물은 기하 및 재료 비선형 거동을 고려할 수 있는 쉘 요소로 모델링한다. 유체의 거동은 acoustic 요소로 구현하고, interface 요소 를 사용하여 구조물과 결합한다. 지반-구조물 상호작용을 고려하기 위해 지반의 근역과 원역을 각각 solid 요소와 perfectly matched discrete layer로 모델링한다. 예제 20만 kl급 액체저장탱크의 지진취약도 해석에 적용하여, 유연한 지반에 구조물이 놓인 경우 부지에 서의 암반노두운동의 증폭 및 필터링으로 인해 지진취약도의 중앙값과 대수 표준편차가 감소하는 것을 관찰할 수 있다.
        4,000원
        10.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oxygen-rich porous carbon is of great interest for energy storage applications due to its improved local electronic structures compared with unmodified porous carbon. However, a tunable method for the preparation of oxygen-rich porous carbon with a special microstructure is still worth developing. Herein, a novel modification of porous carbon with different microstructures is facilely prepared via low-temperature solvothermal and KOH activation methods that employ the coal tar and eight substances, such as cellulose as carbon source and modifier, respectively. By testing the yield, surface group structure, lattice structures, morphology, thermal weight loss, and specific capacitance of carbonaceous mesophase, cellulose–hydrochloric acid is identified as the additive for the preparation of oxygen-rich coal tar-based porous carbon. The obtained porous carbon displays a specific surface area of up to 859.49 m2 g− 1 and an average pore diameter of 2.39 nm. More importantly, the material delivers a high capacity of 275.95 F g− 1 at 0.3 A g− 1 and maintains a high capacitance of 220 F g− 1 even at 10 A g− 1. When in a neutral electrolyte, it can still retain a reversible capacity of 236.72 F g− 1 at 0.3 A g− 1 and 136.79 F g− 1 at 10 A g− 1. This work may provide insight into the design of carbon anode materials with high specific capacity.
        4,500원
        11.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study performed the seismic response analysis of an LNG storage tank supported by a disconnected piled raft foundation (DPRF) with a load transfer platform (LTP). For this purpose, a precise analytical model with simultaneous consideration of Fluid-Structure Interaction (FSI) and Soil-Structure Interaction (SSI) was used. The effect of the LTP characteristics (thickness, stiffness) of the DPRF system on the seismic response of the superstructure (inner and outer tanks) and piles was analyzed. The analytical results were compared with the response of the piled raft foundation (PRF) system. The following conclusions can be drawn from the numerical results: (1) The DPRF system has a smaller bending moment and axial force at the head of the pile than the PRF system, even if the thickness and stiffness of the LTP change; (2) The DPRF system has a slight stiffness of the LTP and the superstructure member force can increase with increasing thickness. This is because as the stiffness of the LTP decreases and the thickness increases, the natural frequency of the LTP becomes closer to the natural frequency of the superstructure, which may affect the response of the superstructure. Therefore, when applying the DPRF system, it is recommended that the sensitivity analysis of the seismic response to the thickness and stiffness of the LTP must be performed.
        4,300원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Application areas of floating marine structure systems have been increased with the development of power generation systems using renewable energy. Hence it is necessary to analyze the behavior of these floating systems for efficient design and operation. In this study, a computational analysis was performed to predict the characteristics of mooring lines load variation connected to a floating marine structure with waves. Pressure on the floating body and mooring lines load were analyzed with wave direction and height. The floating body stability severely decreased for 90° of the wave incident direction, and maximum load of the mooring lines increased with the height. These results are expected to be applicable for optimal design of the marine floating system.
        4,000원
        13.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Special equipment used for snow removal is only used in the winter and must be moved into storage during non-winter seasons. However, when moving heavy equipment using a forklift within a limited space, safety accidents may occur due to deformation and damage due to the worker's limited visibility and excessive loading of heavy objects. In this study, the scissors boom of the developed heavy load transporter was conducted in two cases: link structural analysis and position-based structural analysis. In detail, the link structural analysis covers four cases of stress and safety factor according to material and thickness to optimize the specifications of the material selected during development, and the structural analysis according to position covers two cases before and after the lift, when maximum stress concentration is achieved. Safety was evaluated through finite element analysis. As a result of the study, when manufacturing a scissors boom type heavy load transporter that can withstand a load of 10 tons, the link showed safety at SS400 4.5mm or higher, and reinforcement is needed in the upper and lower structures, so it is judged to be useful in applying materials according to the load.
        4,000원
        14.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the architectural characteristics of Hak-seong Lee Family's Geun-jae-gong Historic House located in Seok-cheon-ri, Ung-chon-myeon, Ulju-gun, Ulsan. The house is said to have been rebuilt in the early 20th century after it was built in the 18th century, and now there are nine buildings left, including the An-chae, Sa-rang-chae, Sa-dang, storehouses and etc. This house is a large-scale house that is difficult to find similar cases in near region. The division of areas on each building is clear, and it is evaluated that it retains the typical characteristics of the head family in the late Joseon Dynasty in terms of its overall size and layout. In addition, the current wooden structure, which is said to have been rebuilt in the early 20th century, shows the composition method and space utilization method of the 3-Dori type upper structure, which have become more diverse since the late Joseon Dynasty. This has not been dealt with in the previous survey, and should be considered in detail through this paper.
        4,000원
        18.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, Free-Form and Irregular Shape high-rise buildings are constructed by IT technology development. Tilted shaped high-rise building which is one of Irregular shape high-rise buildings can cause lateral displacement by gravity load and lateral load due to tilted elevation shape. Therefore, it is necessary to review the behavior and structural aspects of the Tilted shape high-rise building by gravity load. In this paper, the dynamic characteristics of a tilted structure with a dual-core were analyzed with the core location as a design variable, and response behavior, vulnerable members, and vulnerable layers to earthquake loads were analyzed. As a result of the analysis, as the location of the core moved in an tilted direction, the eccentric distance and eccentric load decreased, reducing the axial force of the vertical members. However, the location of the core had little effect on the response.
        4,000원
        19.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 지구 온난화의 영향으로 태풍의 파괴력이 증가함에 따라 부유식 해상풍력발전기의 막대한 유실과 붕괴에 대한 우려가 깊어지고 있다. 부유식 해상풍력발전기의 안전한 운영을 위해 새로운 형태의 탈착형 계류 시스템 개발이 요구되고 있다. 본 연구에서 고 려한 새로운 반잠수식 계류 풀리는 기존의 탈착형 계류 장치에 비해 계류 라인으로 부유식 해상풍력 터빈을 보다 쉽게 탈부착할 수 있도 록 고안되었다. 8MW급 부유식 해상풍력발전기에 적용 가능한 반잠수식 계류 풀리의 초기 설계에 대한 구조적 안전성을 검토하기 위해 3D 프린터를 이용하여 축소구조모형을 제작하고, 이 모형에 대한 구조시험을 수행하였다. 축소 모형의 구조시험을 위해 3D 프린팅에 사 용된 ABS 소재의 인장 시편을 제작하고 인장시험을 수행하여 소재의 물성을 평가하였다. 인장시험에서 얻은 재료 특성과 축소모형 구조 시험과 동일한 하중 및 경계 조건을 적용하여 반잠수식 계류 풀리의 유한요소해석을 수행하였다. 유한요소해석을 통해 반잠수식 계류 풀 리의 구조적 취약 부분을 검토하였다. 반잠수식 계류 풀리의 주요 하중조건을 고려하여 구조모형시험을 수행하였으며, 재료의 최대인장 응력 이상이 발생하는 위치에 대해 유한요소해석과 시험 결과를 비교하였다. 유한요소해석과 모형시험의 결과로부터 작동조건에서는 Body와 Wheel의 연결부 구조가 취약한 것으로 파악되었고, 계류조건에서는 Body와 Chain stopper의 연결부 구조가 취약한 것으로 검토되었 다. 축소모형 구조시험에서 나타난 SMP의 구조 취약부는 구조해석의 결과와 일치하는 것으로 나타났다. 연구 결과를 통해 반잠수식 계류 풀리의 초기 설계에 대한 구조적 안전성을 실험적으로 검증할 수 있었다. 또한, 본 연구 결과는 상세설계 단계에서 반잠수식 계류 풀리의 구조 강도를 향상시키는데 유용하게 활용될 수 있을 것으로 판단된다.
        4,000원
        20.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Epoxy-based composites find extensive application in electronic packaging due to their excellent processability and insulation properties. However, conventional epoxy-based polymers exhibit limitations in terms of thermal properties and insulation performance. In this study, we develop epoxy-based siloxane/silica composites that enhance the thermal, mechanical, and insulating properties of epoxy resins. This is achieved by employing a sol–gelsynthesized siloxane hybrid and spherical fused silica particles. Herein, we fabricate two types of epoxy-based siloxane/ silica composites with different siloxane molecular structures (branched and linear siloxane networks) and investigate the changes in their properties for different compositions (with or without silica particles) and siloxane structures. The presence of a branched siloxane structure results in hardness and low insulating properties, while a linear siloxane structure yields softness and highly insulating properties. Both types of epoxy-based siloxane/silica composites exhibit high thermal stability and low thermal expansion. These properties are considerably improved by incorporating silica particles. We expect that our developed epoxy-based composites to hold significant potential as advanced electronic packaging materials, offering high-performance and robustness.
        4,000원
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