Earticle

본 논문에서는 드론 운용에 사용되는 주파수 대역(433MHz, 915MHz, 2.4GHz, 5.8GHz)의 신호를 탐지하 기 위한 소형 안테나를 기존 결과를 기반으로 설계하였으며, 각 대역의 특성 개선을 위한 파라미터 최적화 결과를 소개하였다. 소개된 안테나는 UHF 대역(433MHz)의 소형화를 위해 접힌구조(meander line)를 사용하였고, 2.4GHz와 5.8GHz 대역의 공진을 위한 추가 패치의 길이를 조절하여 최적의 특성을 구현하였다. 안테나의 기본 구조 설계를 위해 CST MWS를 사용 하였으며, FR-4 유전체(εr=4.3, t=1mm, 136mm(L)x10mm(W))위에 다이폴 구조의 접힌 구조를 설계하였고, 각 대역의 공진을 위해 추가된 패치와 접지면의 크기를 조정하여 각 파라미터를 최적화하였다. 제안된 안테나는 433MHz에서 5.8GHz 대역에서 –1.37dBi, 5.85dBi의 이득을 각각 갖는다. 제안된 안테나는 소형이면서 UHF 대역과 WiFi 대역에서 동시에 활용 가능 한 다중대역안테나로 휴대용 드론 탐지용 시스 템에 사용할 수 있다.

In this paper, we present a small antenna designed based on existing results to detect signals in the frequency bands (433MHz, 915MHz, 2.4GHz, 5.8GHz) used in drone operation and a parameter optimization results to improve the characteristics of each band is introduced. The introduced antenna used a folded structure (meander line) to miniaturize the UHF band (433MHz), and optimized characteristics were achieved by adjusting the length of the additional patch for resonance in the 2.4GHz and 5.8GHz bands. To design the antenna's basic structure, a folded dipole configuration was created on an FR-4 dielectric material (εr=4.3, t=1mm, 136mm(L)x10mm(W)) using CST MWS software. The parameters were optimized for resonance in each desired frequency band by adjusting the dimensions of the added patch and ground plane. The resulting antenna achieves gains ranging from -1.37dBi to 5.85dBi across the 433MHz to 5.8GHz frequency bands. This compact, multi-band planar antenna is suitable for use in both the UHF and WiFi bands, making it ideal for portable drone detection systems.

This study establishes a transient CFD and coupled CFD-thermal analysis method for evaluating the insulation performance of a liquid hydrogen control valve system incorporating an MLI-VCS-MLI configuration. Parametric analysis was conducted by varying the thickness of MLI 2 (50–200 mm) to assess its impact on the temperature distribution and heat flux within the valve body and insulation layers. The results indicate that increasing the thickness of MLI 2 significantly reduces heat flux and improves insulation effectiveness, with the highest heat flux occurring at the outermost MLI layer exposed to ambient conditions. These findings provide valuable insights for optimizing insulation design in liquid hydrogen storage and transport systems, contributing to enhanced thermal management and energy efficiency.

In order to overcome the limitations of linear vibration energy harvesters and those using mechanical plucking, magnetic plucking vibration energy harvesters (MVEs) have garnered significant interest. This paper presents parametric studies aimed at proposing design guidelines for MVEs and compares two magnetic force models that describe interactions between two permanent magnets. A mathematical model describing the energy harvester is employed, followed by the introduction of two magnetic force models: an analytic model and an inverse square model. Subsequently, numerical simulations are conducted to investigate dynamic characteristics of MVEs, analyzing results in terms of tip displacement, voltage output, and harvested energy. Parametric studies vary the distance between magnets, the speed of the external magnet, and the beam shape. Results indicate that reducing the distance between magnets enhances energy harvesting effectiveness. An optimal velocity for the external magnet is observed, and studies on beam shape suggest greater energy harvesting when the shape favors deflection.

중력모형에 의존하여 경제효과를 설명할 경우, 지금까지 주로 패널데이터(panel data) 분석을 통한 개별 고정효과 패널 분석(individual fixed effect)을 수행하였다. 본 연구에서는 기존의 패 널 데이터의 고정효과 분석이 아니라 새로운 인공신경망(Artificial Neural Network)을 이용한 예측을 시도하였다. 특히, 그 중에서도 파라미터부분과 인공신경망의 비-파라미터 방식의 혼 합으로 이루어진 반-모수 패널 신경망(semi-parametric panel neural network)을 방법론으로 채택 하였다. 이 방법을 이용하여, 일본과 한국의 2개 국가에 대하여, 각각의 10년 예측과 5년 예측 의 두 종류의 기간에 대하여, 전통적 고정효과 패널 분석(panel individual fixed effect)과 함께 반-모수 패널 신경망(semi-parametric panel neural network) 분석을 시도하여 총 여덟 종류의 학 습과 예측을 실시하였다. 결과 반-모수패널 인공신경망이 여덟 개 케이스 중에서 일곱 개 케이 스에서 전통적 고정효과 패널 추정 방식보다 예측에서 우수한 결과를 보여 주었다.

Purpose : To compare the predictability of gravity model based on panel data, the two methodologies are used and compared. One comes from the traditional panel individual fixed effects and the alternative methodology comes from semi-parametric panel neural network. Research design, data, methodology : The exporting cases of Korea and Japan, for 30 years of data with 247 countries of export partners, were analyzed. Two scenarios dividing the learning period into 20 years with 10 years’ prediction period and the 25 year learning period with 5 years’ prediction periods are performed and compared. Results : The semi-parametric panel artificial neural network outperformed than the traditional panel fixed effect method in 7 out of 8 cases in terms of MSE. Conclusions : The results showed the superiority of semi-parametric neural networks in the analysis and forecasting based on panel data compared to traditional fixed effect panel analysis.

본 연구는 생산유전에서 다양한 시설 요인과 파라핀 침전 간의 상관성을 제시하였다. 파라핀 침전은 생산 중자주 발생하며, 이는 환경 및 운영조건에 따라 결정된다. 유동관 매설 깊이에 따른 연간 토양온도 변화 추이와의 상관성을 검토하였다. 그리고, 전산유체역학을 통해 인공채유 설비에서 발생한 유동 패턴의 물리적인 영향에 대해 요인평가를 수행하였다. PCP(Progressing Cavity Pump) 시스템에서 rod 주변은 스월(swirl) 유동이 발생하여 rod 표면에는파라핀이 침전이 잘되지 않는다. 또한, 내부 유속이 상승하면 벽면 전단응력의 증가로 점성하위층 두께가 감소하여튜빙 표면에 파라핀 침전량이 감소하는 것으로 나타났다. 생산유전 시설의 파라핀 침전 상황 판단 시, 해당 요인들을추가 고려한다면 더욱 정밀한 평가가 가능할 것으로 기대된다.

In this study, possible relationships between various facility-based factors and paraffin deposition in oil fields are suggested. Paraffin deposition commonly occurs during production and is determined by the environmental and operating conditions. The relevance of changes in annual temperature with burial depth of pipeline was examined and a parametric study was performed with the physical effects of flow patterns generated by artificial lift being evaluated utilizing Computational Fluid Dynamics(CFD) simulation. Paraffin was difficult to deposit on the surface of the rod, owing to the swirling flow generated around the rod in the Progressing Cavity Pump(PCP) system. In addition, a decrease in paraffin deposition was seen on the tubing surface, with the viscous sub-layer thickness determined by the wall shear stress depending upon the inlet velocity. When estimating paraffin deposition in an oil field, it is expected that more accurate evaluations will be possible if the suggested factors are taken into consideration.

Globally, there is a concentrated effort to lead in alternative energy technologies. Among various eco-friendly energy sources and carbon-free fuels, hydrogen energy is gaining attention as a clean energy solution for future industries, as its only byproduct is water. There are two primary storage methods: compressing hydrogen gas at high pressure and storing it as a liquid. Research on insulation, including the structural design of multi-layer Insulation (MLI) and vapor-cooled shield (VCS), as well as the materials used for insulation, has been actively conducted. However, studies focused on improving the structural safety of the supports that sustain the structure between the inner and outer tanks have been limited. In this study, a thermal-structural coupled analysis technique for liquid hydrogen storage tanks was developed using commercial finite element analysis software for the design of support structures for liquid hydrogen storage tanks. Six analytical models were created based on varying the number and diameter of the supports with the constant total volume of the supports and a structurally safe support configuration was proposed.

The development of a high pressure cleaning system is needed to properly clean cargo hold and improve the working environment of a ship. For this, the study on the parameters related to the suitable capacity of a pressure pump should be preceded.

In this study, theoretical analyses are performed to investigate the characteristics of the static and dynamic stiffness of a nonlinear vibration isolator system. The vibration isolator system is modeled as an equivalent nonlinear oscillator. Based on the model, the static equilibrium and frequency response solutions are obtained with the variations of external static load and/or system parameters. It is shown that the static stiffness of the nonlinear vibration isolator tends to be hardened with the increase of external static load, which prevents the occurrence of excessively large deflection. This static stiffness-hardening effect is more remarkable with a larger spring constant ratio. The dynamic stiffness is also strengthened when the spring constant ratio increases, which enlarges the force transmissibility and reduces the isolation frequency bandwidth. Thus, the static stiffness- hardening improves the robustness of the nonlinear vibration isolator, whereas the dynamic stiffness-hardening rather degrades its performance. Thus, the opposite tendency of the static and dynamic stiffness-hardening effects should be considered in the design process of the nonlinear vibration isolator.

In this study, the frequency response analysis of a bistable electromagnetic vibration energy harvester is performed, based on an electromagnetic oscillator model, to investigate its nonlinear dynamic behaviors. The displacement and current responses are obtained, by the direct integration of the model, with the variations of mechanical and electromagnetic parameters. It is shown that the operating frequency band of the system can be broadened by the increase in mechanical parameters(inertial mass and Q-factor), but it does not depend significantly on any electromagnetic parameters(an external load resistance and the internal resistance of a coil). On the other hand, the output current of the energy harvester is affected only by the electromagnetic parameters (specifically, the sum of two resistances). Thus, the mechanical and electromagnetic parameters of the electromagnetic energy harvester must be designed properly, respectively, for broader and more efficient performance.

본 연구는 경력단절 여성의 소득 및 고용 궤적을 분석하여 그 유형과 결정요인을 밝히는 것을 목표로 하였다. 한국여성가족패널(KLoWEP) 데이터를 사용하여 재취업 경력단절 여성의 소득 및 고용 궤적을 분석하였으며, 이를 위해 SPSS 26.0과 SAS 9.4 그리고 TRAJ 프로시저를 사용하였다. 분석 결과, 소득과 고용 지위 궤적의 각 유형은 다양하게 나타났으며, 이는 가구소득, 남편의 소득, 취학 자녀 수, 비공식 돌봄 및 가사노동 제공자, 첫 직장 종사상지위, 남편의 아내 취직에 대한 태도 등과 관련이 있었다. 이를 통해 경력단절 여성의 노동시장 재진입은 단순한과정이 아니라 다양한 요인에 영향을 받음을 확인하였으며, 이를 고려한 정책 및 프로그램이 필요하다는 결론을 도출하였다. 또한, 비공식 돌봄 및 가사노동 제공자의 존재, 첫 직장의 종사상 지위와 재진입 이후 초기 고용 지위 수준이 노동시장 재진입 이후 궤적 유형 결정에 영향을 미친다는 점이 확인되었다. 이에 남성의 돌봄 책임을 반영한 일 가정 양립 패러다임의 개발과 여성에 대한 실질적인 개입을 통해 경력단절여성 문제를 해결해야 한다.

This study aims to analyze the income and employment trajectories of career-interrupted women to identify their types and determinants. Using data from the Korean Longitudinal Survey of Women and Families (KLoWEP), we analyzed the income and employment trajectories of reemployed career-interrupted women. For this analysis, we utilized SPSS 26.0, SAS 9.4, and the TRAJ procedure. The results revealed diverse types of income and employment status trajectories, which were associated with household income, husband’s income, the number of school-aged children, providers of informal care and household labor, initial job status, and the husband’s attitude toward his wife’s employment. This study confirms that re-entering the labor market for career-interrupted women is not a simple process but is influenced by various factors, highlighting the need for policies and programs that take these factors into account. Additionally, it was confirmed that the presence of informal caregivers and household labor providers, the employment status of the first job, and the level of initial employment status after re-entry influenced the determination of trajectory types after re-entering the labor market. Therefore, it is necessary to address the issue of career-interrupted women through the development of a work-family balance paradigm that reflects men’s caregiving responsibilities and through substantial interventions for women.

This study is aimed at proposing the following two possibilities and analyzing them in connection with the positions of objects in Old French(OF) (11c-12c): i) Can objects move to the left position of a clause by means of Object Shift? and ii) Does the object raising comply with the feature inheritance theory proposed by Chomsky(2008) in order to realize the V2-structure of OF constructions? Although these two syntactic operations have quite close relations, we will verify which parameter can apply to them in OF considering that they operate in a different manner among languages. Consequently, we will observe and analyze the following subjects: i) The trigger in C is a tense feature which causes a finite verb to raise to C; ii) What moves an object to Spec-CP is an edge feature in C?; iii) How is the OF object raising different from the object shift?; iv) How can the status of lexical or null subject be determined during the OF object raising/shift?; v) Is the object raising/shift derived from the verb movement and the feature inheritance in OF? Shedding light on these tasks, we will clarify that the object raising/shift can be verified by the verb movement and feature inheritance in the object raising constructions observed in La Chanson de Roland(1090) and Le Chevalier de la Charrete(1179-81).

This paper is aimed at analysing some parametric variation involved in impersonal-il extraposition constructions in French. These French constructions, generally considered as corresponding to English counterparts that weren't taken care of here, manifest a wider variety of parametric variation in their syntactic operations. We verified that this kind of variation in French is based on the distinct morpho-lexical features of expletive-il, thus having [3rdpers, masc, sing, nom] features. In addition, the pronominal feature of French expletive-il has to be checked through the agreement with the following verb. This fact means that French expletive-il cannot be placed in the real (semantic) subject positions in infinitival and gerundival constructions

This study aims at analyzing the quotative inversion constructions(QIC) in Old/Medieval/Modern French, and verifying their parametric variations from the syntactic, semantic and pragmatical point of view. Although the QICs in Old French are somewhat rare in their frequency, we will compare them with the Medieval French counterparts. Following the analytical results derived from the rules and constraints in Modern French QICs, we will apply them to those in Old/Medieval French. Consequently, we will observe and deal with the following parametric variations: First, why does the finite verb raise to C, and what is its trigger? Second, what are the syntactic factors that move the quotes(direct speech complements) to SPEC-CP? Third, how can the syntactic properties of subject DP(of main clause) and quotes be explained in Old/Medieval QICs? and what is different from those in ModF? Fourth, are the quotes controlled by V2 as an element of main clause, or do they constitute an independent clause? Finally, are the QICs in Old/Medieval excluded from the parallel movement applied in ModF? The texts adopted in this study are La Chanson de Roland(11-12c, OF), Le Chevalier de la Charette(12-13c, OF), and La Vie de Saint Louis(14c, MF), Les Quinze Joies du Mariage(15c, MF)

The use of various digital tools makes freeform modeling possible. At the same time, with the development of structural and construction technologies, Free-Form Architecture are beginning to be implemented realized, as the desired data extraction such as the size and coordinate points of the members is possible. Currently, in many cities around the world, Irregular-Shaped High-rise Buildings, which express the dynamic symbolism, are recognized for their landmark values. In order to realize the Irregular-Shaped High-rise Buildings, it is necessary to understand various fields such as the characteristics of digital tools, digital technique logic, design process, and construction method. In particular, it is important to plan Irregular-Shaped High-rise Buildings so that the various types of efficiency can be reviewed together, while generating understanding and formations from the initial design stage. Therefore, this study uses conceptual and parametric design tools related to form generation in digital architecture to analyze the details, methods, and characteristics of the Irregular-Shaped High-rise Buildings form generation process. In this paper, the parametric design tool is applied to study the various types of design and the process characteristics that can be considered in the initial design stage of the unstructured skyscraper.

본 연구는 파라메트릭 디자인 기반의 3D프린팅 패션제품이 늘어나고 있는 가운데, 3D프린팅 파라메트릭 패션제품의 조형성을 탐구하는 것을 목표로 한다. 연구방법으로, 이론적 고찰을 실시하고 3D프린팅 파라메트릭 패션제품의 조형성을 도출한뒤, 3D프린팅 파라메트릭 패션제품의 사례를 수집하여 의류, 신발, 악세사리 총 3가지 유형으로 살펴보았다. 연구결과, 형태적으로는 자연물을 모티브로한 형태를 확인할 수 있었고, 구조적으로는 경제 적인 최적구조와 어셈블리구조, 자연물 구조를 확인하였으며 소재의 경우는 복잡형상 구현을 위한 정밀소재를, 색채의 경우는 단색, 무채색 계열과 자연색조합을 사용한다는 것을 알 수 있었다. 본 연구에서 제시한 3D프린팅 파라메트릭 패션제품의 조형성에 대한 이해를 통해 파라메트릭 기반 패션제품의 확산과 조형적 흐름을 이해하는데 기초자료로 사용되기를 기대한다.

This study aims to explore the formativeness of 3D printed parametric fashion products while parametric design-based 3D printed fashion products are increasing. As a research method, theoretical review was conducted and formative properties of 3D printing parametric fashion products were derived, and cases of 3D printing parametric fashion products were collected and examined into three types of clothing, shoes, and accessories. As a result of the study, it was possible to confirm the shape with the motif of a natural object, and structurally, the economical optimal structure, assembly structure, and natural structure were confirmed. was found to use natural and achromatic colors. Through the understanding of the formativeness of 3D printing parametric fashion products presented in this study, it is expected that it will be used as basic data to understand the spread and formative flow of parametric-based fashion products.

This paper is aimed at analysing the Locative Inversion(LI) Constructions in Old French from modern syntactic point of view. For this purpose, we adopt the feature inheritance proposal of Chomsky (2008) and its revised and reinterpreted version of Goto(2008), which will be slightly modified for our analysis. The problems we have to solve are summarized by the following three questions. First, what can be an attractor triggering the finite-verb movement? Second, what will move a locative phrase to the position of Spec-CP? Third, can LI with null subject and LI with lexical subject have the same syntactic procedures or do they have to be distinguished from each other? After analyzing these problems with above-mentioned proposals, we conclude that they can be addressed by the parallel movement and our revised version of feature inheritance system. Finally, we make a comparative list of Old French LI Constructions in order to observe differences in parametric variation. (Youngsan University)

This paper is aimed at analysing the interrogative constructions in Old French from modern syntactic point of view. For this purpose, we adopt the feature inheritance proposal of Chomsky(2008) and its revised and reinterpreted version of Goto(2008), which will be slightly modified for our analysis. The problems we have to solve are summarized by the following three questions. First, what can be an attractor triggering the finite-verb movement? Second, what will move a wh-phrase to the position of Spec-CP? Third, how can the distinction between a nominal subject movement and a clitic subject movement be accounted for in inverted interrogatives? After analyzing these problems with above-mentioned proposals, we conclude that they can be addressed by the parallel movement and our revised version of feature inheritance system. Finally, we make a comparative list of Old French interrogatives in order to observe differences in parametric variation

비정형건축의 형태는 다양한 곡률을 가진 곡면으로 구성된다. 이러한 곡면은 디지털 테크놀로지의 발전에 힘입어 형태 디자인이 가능하게 되었지만, 설계 및 시공단계에서 자유곡면의 구현에 많은 난관이 존재한다. 특히 부재의 생산, 시공성의 확보, 패널의 최적화 단계에서 기술적 어려움이 산재해 있다. 이러한 현상은 디자인된 곡면의 수학적 정의가 어렵고 일반적인 정형의 건축과는 다른 설계 과정을 필요로 하기 때문이다. 비정형 초고층건물의 경우, 비정형 건축의 자유곡면 해석과 초고층건물의 특성을 함께 고려하여야 하기 때문에 지속적인 연구가 요구되고 있다. 따라서 본 연구에서는 선행연구의 비정형 초고층건물의 형태별 분류 및 다양한 곡면분할 프로세스를 바탕으로, 비정형 초고층건물의 형태별 곡면분할방식을 분석하고, 각 형태 및 곡면분할방식별 분할이 가능한 파라메트릭 툴을 구축하여 실제 모델에 적용해봄으로써 그 효용성을 확인해 보고자 한다.

Recently, the planning and construction of the irregular architecture are increasing. Form of irregular shaped architecture is to pursue expressionistic free-form through not straight line but curve which has various curvature. Although the development of digital technology enables irregular shaped architecture, there are many difficulties in realization of the curved surface in the design and construction phases. In particular, there are technical difficulties during the optimization phase of panels such as the producing of element, securing construct ability, keeping the original curved surface. These phenomena is because the mathematical definition of designed curved surfaces is difficult and the irregular shaped architecture require a different design process from the common shaped architecture. In case of irregular-shaped tall buildings, The continuous research is required because architects consider analyzing curved surface of irregular shaped architecture and characterization of tall buildings. Many researches are about the space planning and structure of irregular-shaped tall buildings. However, the process of Curved-surface division is rare in the field. So in this study, we propose reasonable process to develop Curved-surface division and analyze the characteristics of the irregular-shaped tall building facade.