• Smart Structures and Systems
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• 제21권3호
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• pp.279-286
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• 2018

The free longitudinal vibration of a circular truncated nanocone is investigated based on the nonlocal elasticity theory. Exact analytical formulations for tapered nanostructures are derived and the nonlinear differential governing equation of motion is developed. The nonlocal small scale effect unavailable in classical continuum theory is addressed to reveal the long-range interaction of atoms implicated in nonlocal constitutive relation. Unlike most previous studies applying the truncation method to the infinite higher-order differential equation, this paper aims to consider all higher-order terms to show the overall nonlocality. The explicit solution of nonlocal stress for longitudinal deformation is determined and it is an infinite series incorporating the classical stress derived in classical mechanics of materials and the infinite higher-order derivative of longitudinal displacement. Subsequently, the first three modes natural frequencies are calculated numerically and the significant effects of nonlocal small scale and vertex angle on natural frequencies are examined. The coupling phenomenon of natural frequency is observed and it is induced by the combined effects of nonlocal small scale and vertex angle. The critical value of nonlocal small scale is defined, and after that a new proposal for determining the range of nonlocal small scale is put forward since the principle of choosing the nonlocal small scale is still unclear at present. Additionally, two different types of nonlocal effects, namely the nonlocal stiffness weakening and strengthening, reversed phenomena existing in nanostructures are observed and verified. Hence the opposite nonlocal effects are resolved again clearly. The nano-engineers dealing with a circular truncated nanocone-based sensors and oscillators may benefit from the present work.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.83-88
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• 2006

Many applications in the area of location-based services and personal navigation require nowadays the location determination of a user not only in outdoor environment but also indoor. To locate a person or object in a building, systems that use either infrared, ultrasonic or radio signals, and visible light for optical tracking have been developed. The use of WiFi for location determination has the advantage that no transmitters or receivers have to be installed in the building like in the case of infrared and ultrasonic based location systems. WiFi positioning technology adopts IEEE802.11x standard, by observing the radio signals from access points installed inside a building. These access points can be found nowadays in our daily environment, e.g. in many office buildings, public spaces and in urban areas. The principle of operation of location determination using WiFi signals is based on the measurement of the signal strengths to the surrounding available access points at a mobile terminal (e.g. PDA, notebook PC). An estimate of the location of the terminal is then obtained on the basis of these measurements and a signal propagation model inside the building. The signal propagation model can be obtained using simulations or with prior calibration measurements at known locations in an offline phase. The most common location determination approach is based on signal propagation patterns, namely WiFi fingerprinting. In this paper the underlying technology is briefly reviewed followed by an investigation of two WiFi positioning systems. Testing of the system is performed in two localization test beds, one at the Vienna University of Technology and the second at the Hong Kong Polytechnic University. First test showed that the trajectory of a moving user could be obtained with a standard deviation of about ${\pm}$ 3 m.

• 철학연구
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• 제146권
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• pp.1-24
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• 2018

본 논문의 목적은 생명윤리에 대한 이론 윤리학이 갖는 의미를 탐색하는데 있다. 첫 번째로 싱어가 제시하고 있는 이익평등고려의 원칙과 선호공리주의가 생명윤리 분야 내에서 어떠한 의미와 한계점을 갖는지 살펴본다. 두 번째로 칸트 윤리학이 생명윤리 분야에서 갖는 중요성을 강조해 보고, 그럼에도 부족했던 관점을 알아본다. 마지막으로 아리스토텔레스의 덕윤리가 생명윤리로 실현되어야 하는 이유를 살펴보고, 이를 통해 인간 삶의 의미를 제언하고자 한다. 싱어의 주장은 기존 윤리학사(倫理學史)에서 고려하지 못했던 진화한 생명에 대한 새로운 화두를 던져준다. 그는 당연시 되었던 인간 존엄에 대해 부정할 수 없는 차원의 의견을 제시하였다고 볼 수 있다. 또한, 생명 존중 대상에 대한 범위 확장을 합리적으로 이루었다고 평가할만하다. 이와 구분하여, 칸트 윤리학은 인간 존엄의 의미를 형이상학적 의미를 근거하여 설명한다. 더 나아가 인간 삶의 올바른 방향성을 제시한다. 그들의 주장을 수용함에도 결핍되었던 삶의 의미는 아리스토텔레스의 덕윤리의 적용을 통해 해소될 수 있을 듯하다. 인간을 비롯한 존재자의 삶의 의미는 생명, 더 나아가 존재 자체에 내재된 것일 수 있다.

• 한국연극학
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• 제49호
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• pp.49-71
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• 2013

Melodrama emerged as a form of the moral in the early modern age. As an approach 'the moral' not only means that rewarding virtue and punishing vice, but also refer to a principle of spiritual life and a way of life. -Melodrama theatricalizes a new vision of human life and society through a new type of the virtuous protagonist and sentiment/-ality. -This allows melodrama to be a dominant cultural form in this modern age, beyond the borders of the theater, mass-media, and literature. Virtue and sentiment/-ality are the core elements of melodrama, which differentiate it from tragedy and comedy especially in the structure and effect of the drama. Actually virtue and sentiment/-ality have been a main target of criticism. Virtue has been regarded as a trite quality of the stereotypical protagonist, and sentiment/-ality as a banal emotion which paralyzes an audience's recognition of reality. -However, this thesis regards both virtue and sentiment/-ality as vehicles for showing and sharing the morals of the modern age. First, the virtues of the protagonist included the general and universal ones of the bourgeois -at that times, the bourgeois represented themselves as a human being- such as the responsibility and obedience of a father, a mother, a wife, a husband, a daughter and a son. They also included the professional ethics such as courage, honesty, and justice and so on. The fall or salvation of the protagonist is largely determined by his/her private individual virtue. Second, sentiment/ality is a theatrical device that makes the audience internalize the protagonist's virtue. The protagonist expresses his/her universal virtue sentimentally, and the audience also expresses their virtue by sympathizing with the protagonist's virtue sentimentally. However, the melodramatic protagonist as an individual, is not connected with society, but remains isolated. As a result, s/he has no influence on the society, where s/he can only ends her/his play alone with a happy-ending. S/he is happy alone, or at best happy with his/her own family. On the contrary to this, tragic protagonist usually fixes social disorder through his/her fall. In that sense, we can say that melodrama presents only the half of the human life.

• 한국재료학회지
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• 제29권7호
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• pp.451-455
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• 2019

The electromagnetic and thermal properties of a heavy fermion $CeNi_2Ge_2$ are investigated using first-principle methods with local density approximation (LDA) and fully relativistic approaches. The Ce f-bands are located near the Fermi energy $E_F$ and hybridized with the Ni-3d states. This hybridization plays important roles in the characteristics of this material. The fully relativistic approach shows that the 4f states split into $4f_{7/2}$ and $4f_{5/2}$ states due to spin-orbit coupling effects. It can be found that within the LDA calculation, the density of states near the Fermi level are mainly of Ce-derived 4f states. The Ni-derived 3d states have high peaks around -1.7eV and spreaded over wide range around the Fermi level. The calculated magnetic of $CeNi_2Ge_2$ with LDA method does not match with that of experimental result because of strong correlation interaction between electrons in f orbitals. The calculations show that the specific heat coefficient underestimates the experimental value by a factor of 19.1. The discrepancy between the band calculation and experiment for specific heat coefficient is attributed to the formation of a quasiparticle. Because of the volume contraction, the exchange interaction between the f states and the conduction electrons is large in $CeNi_2Ge_2$, which increases the quasiparticle mass. This will result in the enhancement of the specific hear coefficient.

• 기록학연구
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• 제61호
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• pp.31-69
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• 2019

본 연구는 국내 문학관에 분산 소장되어 있는 작가의 문학자료에 대한 기록학적 탐구와 기록관리 적용에 관한 검토를 통해 문학기록에 적합한 조직방안을 모색하고자 한다. 먼저 문헌 연구와 사례 분석을 통해 문학 기록의 특성과 가치에 적합한 조직화를 위한 '원질서의 원칙'을 탐구했다. 다음으로 '디아스포라 아카이브'를 사례로 문학기록 조직화에 적합한 모형을 도출한 후, 국내 지역문학관에 '분산 컬렉션'의 형태로 존재하는 작가 조정래(1943~)의 문학자료를 대상으로 조직 모형을 적용하였다. 연구결과 조정래 작가의 '분산 컬렉션'에 통합적으로 접근하기 위하여 ICA AtoM 기반 '기록-작가-문학관' 관련 기술정보를 연계하여 단일한 게이트웨이를 통하여 제공하는 모형을 제안하였다. 아울러 개별 문학관의 소장 자료도 기록 조직화의 원칙에 따라 계층적 분류체계를 적용하여 기존의 건별 목록에 비하여 보다 풍부한 집합적 맥락적 정보를 제공할 수 있도록 하였다.

• Steel and Composite Structures
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• 제30권2호
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• pp.109-121
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• 2019

This paper presents the second part of the modeling for the strap combined footings, this part shows a mathematical model for design of strap combined footings subject to axial load and moments in two directions to each column considering the soil real pressure acting on the contact surface of the footing for one and/or two property lines of sides opposite restricted, the pressure is presented in terms of an axial load, moment around the axis "X" and moment around the axis "Y" to each column, and the methodology is developed using the principle that the derived of the moment is the shear force. The first part shows the optimal contact surface for the strap combined footings to obtain the most economical dimensioning on the soil (optimal area). The classic model considers an axial load and a moment around the axis "X" (transverse axis) applied to each column, i.e., the resultant force from the applied loads is located on the axis "Y" (longitudinal axis), and its position must match with the geometric center of the footing, and when the axial load and moments in two directions are presented, the maximum pressure and uniform applied throughout the contact surface of the footing is considered the same. A numerical example is presented to obtain the design of strap combined footings subject to an axial load and moments in two directions applied to each column. The mathematical approach suggested in this paper produces results that have a tangible accuracy for all problems and it can also be used for rectangular and T-shaped combined footings.

• 식품과학과 산업
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• 제49권2호
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• pp.83-97
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• 2016

본 총설은 음식윤리의 개요를 식품과학과 산업 분야의 전문인에게 설명하고자 한 것이다. 음식윤리는 음식과 관련된 윤리 또는 윤리적 고려이고, 음식윤리의 핵심어는 생명, 행복, 지혜이다. 음식윤리의 제1원리이자 궁극적인 목적은 인류의 지속가능한 생존이다. 그 목적을 달성하기 위해서는 자연과의 공생, 인간과의 공생, 그리고 음식의 본질적 요소의 충족이 필요하다. 그 필요로부터 생명존중, 자연보전, 속임수나 가짜가 없는 분배의 정의, 소비자 최우선 고려, 절제와 균형, 그리고 안전성 확보의 여섯 가지 정언명령이 산출된다. 정언명령에 상응하는 핵심원리는 생명존중, 환경보전, 정의, 소비자 최우선, 동적 평형, 안전성 최우선이다. 핵심원리 접근법은 윤리문제의 해결에 간단하고 명료하며 실질적인 방법이다. 음식윤리강령 역시 핵심원리를 기반으로 한다.

• Structural Engineering and Mechanics
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• 제81권2호
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• pp.179-194
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• 2022

The bending, buckling and free vibration responses of functionally graded material (FGM) beams are investigated semi-analytically by the scaled boundary finite element method (SBFEM) in this paper. In the concepts of the SBFEM, the dimension of computational domain can be reduced by one, therefore only the axial dimension of the beam is discretized using the higher order spectral element, which reduces the amount of calculation and greatly improves the calculation efficiency. The governing equation of FGM beams is derived in detail by the means of the principle of virtual work. Compared with the higher-order beam theory, fewer parameters and simpler control equations are used. And the governing equation is transformed into a first-order ordinary differential equation by introducing intermediate variables. Analytical solutions of the governing equation can be obtained by pade series expansion in the direction of thickness. Numerical example are compared with the numerical solutions provided by the previous researchers to verify the accuracy and applicability of the proposed method. The results show that the proposed formulations can quickly converge to the reference solutions by increasing the order of higher order spectral elements, and high accuracy can be achieved by using a small number of the elements. In addition, the influence of the structural sizes, material properties and boundary conditions on the mechanical behaviors of FG beams subjected to different load types is discussed.

• Structural Engineering and Mechanics
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• 제84권4호
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• pp.437-452
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• 2022

For the first time, the higher-order shear and normal deformable plate theory (HOSNDPT) is used for the vibration and flutter analyses of the multilayer functionally graded graphene platelets reinforced composite (FG-GPLRC) plates under supersonic airflow. For modeling the supersonic airflow, the linear piston theory is adopted. In HOSNDPT, Legendre polynomials are used to approximate the components of the displacement field in the thickness direction. So, all stress and strain components are encountered. Either uniform or three kinds of non-uniform distribution of graphene platelets (GPLs) into polymer matrix are considered. The Young modulus of the FG-GPLRC plate is estimated by the modified Halpin-Tsai model, while the Poisson ratio and mass density are determined by the rule of mixtures. The Hamilton's principle is used to obtain the governing equations of motion and the associated boundary conditions of the plate. For solving the plate's equations of motion, the Galerkin approach is applied. A comparison for the natural frequencies obtained based on the present investigation and those of three-dimensional elasticity theory shows a very good agreement. The flutter boundaries for FG-GPLRC plates based on HOSNDPT are described and the effects of GPL distribution patterns, the geometrical parameters and the weight fraction of GPLs on the flutter frequencies and flutter aerodynamic pressure of the plate are studied in detail. The obtained results show that by increasing 0.5% of GPLs into polymer matrix, the flutter aerodynamic pressure increases approximately 117%, 145%, 166% and 196% for FG-O, FG-A, UD and FG-X distribution patterns, respectively.