• 대한조선학회지
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• 제20권3호
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• pp.17-20
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• 1983

There have been many investigations of predicting the added resistance of a ship in seaway since Havelock discussed this topic in 1937. Among these researches, Maruo's theoretical approach is known as the most consistent mathematical representation for added resistance of a ship in regular head sea. In his theory, the hull form of a ship is represented under the slender body approximation. But the motion responses which were used for the calculation of the added resistance have been obtained by using the strip method which is based on an approximation that the hull form may be expressed as set of two dimensional cylinder sections in longitudinal direction. Therefore two different methods for hull form representation were implicity used in Maruo's original work for the added resistance calculation. Utilizing the characteristics that hull forms are usually slender, Kan expressed the hull form as two dimensional cylinder at each station by using the Taylor series expansion for the length wise direction. Putting this idea into Maruo's original work, the added resistance can be obtained with the explicitly unique representation of the hull form. For the purpose of comparison the added resistance of a hull form(series 60, Cb=0.6) was calculated by using the motion response obtained by Shintani. The numerical result showes a good qualitative agreement with the experimental result by Sibul.

• 한국기계연구소 소보
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• 통권9호
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• pp.193-208
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• 1982

Flap type wave-maker, wave absorber, motion measuring equipment and related instruments were newly installed at Ship Experimental Towing Tank, Ship Research Station, KIMM. The model tests in regular head and following waves were successfully carried out and the motion and wave loads in regular and long crested irregular waves were calculated for a container ship model which was adopted as the hull form for the comparative calculations of the ITTC Seakeeping Committee. The results of model tests show good agreement with calculated results and the latter are generally in good agreement with the results of the comparative calculations.

• 대한수학회보
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• 제44권4호
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• pp.753-761
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• 2007

In this note we extend the results of [3] concerning subadditive separating maps from A=C(X) to B=C(Y), for compact Hausdorff spaces X and Y, to the case where A and B are regular Banach function algebras(not necessarily unital) with A satisfying Ditkin#s condition. In particular we describe the general form of these maps and get a result on continuity of separating linear functionals.

• 한국수학교육학회지시리즈A:수학교육
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• 제53권4호
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• pp.493-507
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• 2014

The purpose of this study is to analyze how high school students form and interpret the mental image in the process of solving regular polyhedron problems. For this purpose, a set of problems about the regular polyhedron's vertex is developed on the base of the regular polyhedron's duality and circulation. and applied to 2 students of the 12th graders in D high school. After 2 hours of teaching and learning and another 2 hours of mental image-analysis process, the following research findings are obtained. Fisrt, a student who recorded medium high-level grade in the national scholastic test can build the dynamic image or the patten image in the process of solving regular polyhedron's vertex problems by utilizing the 3D geometry program. However, the other student who recorded low-level grade can build the concrete-pictorial image. Second, pattern image or dynamic image can help students solve the regular polyhedron's vertex problems by proper transformation of informations and the mental images while the concrete-pictorial image does not help. Hence, it is recommended that the mathematics teachers should develop teaching and learning materials about the regular polyhedron's duality and circulation and also give students suitable questions to build the various mental images.

• Earthquakes and Structures
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• 제10권1호
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• pp.25-51
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• 2016

In this study, graph product rules are applied to the dynamic analysis of regular skeletal structures. Graph product rules have recently been utilized in structural mechanics as a powerful tool for eigensolution of symmetric and regular skeletal structures. A structure is called regular if its model is a graph product. In the first part of this paper, the formulation of time history dynamic analysis of regular structures under seismic excitation is derived using graph product rules. This formulation can generally be utilized for efficient linear elastic dynamic analysis using vibration modes. The second part comprises of random vibration analysis of regular skeletal structures via canonical forms and closed-form eigensolution of matrices containing special patterns for symmetric structures. In this part, the formulations are developed for dynamic analysis of structures subjected to random seismic excitation in frequency domain. In all the proposed methods, eigensolution of the problems is achieved with less computational effort due to incorporating graph product rules and canonical forms for symmetric and cyclically symmetric structures.

• Macromolecular Research
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• 제8권3호
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• pp.103-115
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• 2000

The structural changes viewed from the molecular level have been investigated for the isothermal crystallization phenomena of polyethylene (PE) and the solvent-induced crystallization phenomenon of syndiotactic polystyrene (sPS) glassy sample. The data, which were collected by the time-resolved measurements of Fourier-transform infrared spectra, Raman spectra, synchrotron-sourced small-angle X-ray scattering, wide-angle X-ray scattering, and so on, were combined together to extract the detailed structural information in these phase transition phenomena. In the case of PE, the isothermal crystallization from the melt to the orthorhombic form was found to occur via the conformationally-disordered trans chain form, followed by the formation of the lamellar stacking structure of regular orthorhombic-type crystals. In the case of sPS, the amorphous chains in the glassy sample were found to enhance the mobility through the interaction with the injected solvent molecules, which act as a trigger to cause the conformational ordering from the random coil to the regular T$_2$G$_2$-type helical form. The thus created short helical segments were found to grow into longer helices, which gathered together to form the crystallites, as revealed by the organized coupling of the infrared, Raman and X-ray scattering data.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권5호
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• pp.499-508
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• 2017

This paper uses optimization techniques to obtain bow hull form of a 66,000 DWT bulk carrier in calm water and in waves. Parametric modification functions of SAC and section shape of DLWL are used for hull form variation. Multi-objective functions are applied to minimize the wave-making resistance in calm water and added resistance in regular head wave of ${\lambda}/L=0.5$. WAVIS version 1.3 is used to obtain wave-making resistance. The modified Fujii and Takahashi's formula is applied to obtain the added resistance in short wave. The PSO algorithm is employed for the optimization technique. The resistance and motion characteristics in calm water and regular and irregular head waves of the three hull forms are compared. It has been shown that the optimal brings 13.2% reduction in the wave-making resistance and 13.8% reduction in the added resistance at ${\lambda}/L=0.5$; and the mean added resistance reduces by 9.5% at sea state 5.

• 산업노동연구
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• 제17권1호
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• pp.139-176
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• 2011

민주노조운동과 노동계급 형성의 후퇴기에 비정규직 노동자들이 투쟁과 함께 새로운 계급형성의 잠재적 주체로 등장했다. 하지만 주체 형성의 효과는 아직 나타나지 않고 있다. 그렇다면, 왜 투쟁은 성과를 내지 못했는가? 어떤 변인들과 인과적 메커니즘을 통해 투쟁의 성과가 결정되는가? 이러한 물음들에 대한 답변을 구하는 것이 본 연구의 목적이다. 정규직 투쟁에 비해 비정규직 투쟁은 자본의 공세에 대응하는 수세적 방어적 성격이 짙고, 생산현장 접근성 제약으로 파업 투쟁 이외의 방식에 의존하며, 사측의 비타협성으로 인해 장기화되고, 교착상태를 타개하기 위해 극단적 투쟁 방식에 호소하며, 정규직 연대 확보가 어려워 외부연대에 크게 의존하는 차별성을 지니고 있다. 비정규직 투쟁은 승리보다는 패배, 조직력 강화보다는 약화로 귀결되는 경향이 강하다. 패배 경향성을 상쇄하고 승리하기 위해서는 비정규직 주체들의 조직 동원 역량과 정규직 노조의 연대가 절대적으로 필요한 조건이며, 강력한 사회적 연대나 위치적 권력은 정규직 연대의 대체재 역할을 할 수 있다. 또한, 투쟁이 조직력 강화로 이어지기 위해서는 투쟁의 승리가 필요하지만 투쟁의 승리로 쟁취한 정규직화가 승리의 덫이 될 수도 있다. 정규직 노조의 연대와 투쟁 주체의 내적 통합은 비정규직 투쟁이 승리하고 조직력을 강화하는데 크게 기여하는 것으로 나타났다. 투쟁을 전개하는 부분은 비정규직 노동자들 가운데 조직력이 가장 강한 부분인데 이들이 투쟁 과정에서 조직력 위축 혹은 조직 와해를 겪으면서 비정규직 주체 형성을 어렵게 한 것이다. 하지만, 비정규직 투쟁이 없었더라면 자본의 공세가 그대로 관철되었을 것이라는 점에서 비정규직 투쟁은 적어도 자본의 공세를 약화 혹은 지연시킨 효과는 거두었다고 할 수 있다. 또한 유형 설정자 역할의 부담 속에서 강경투쟁 전략과 양보타협 전략 사이의 투쟁 전략 딜레마는 투쟁 주체의 분열을 심화하여 투쟁의 승패와 조직력 변화에 부정적 영향을 미치게 된다. 비정규직 투쟁의 실천적 함의는 비정규직 투쟁의 궁극적 목표를 노동계급 형성을 위한 주체형성으로 재정의한다면 비정규직 투쟁의 전략적 목표는 당면 요구조건의 완전한 쟁취보다 조직의 보전 강화에 두는 것이 합리적 선택이라는 점이다.

• 호남수학학술지
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• 제36권3호
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• pp.569-596
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• 2014

In several applied disciplines like control engineering, computer sciences, error-correcting codes and fuzzy automata theory, the use of fuzzied algebraic structures especially ordered semi-groups and their fuzzy subsystems play a remarkable role. In this paper, we introduce the notion of (${\in},{\in}{\vee}\bar{q}_k$)-fuzzy subsystems of ordered semigroups namely (${\in},{\in}{\vee}\bar{q}_k$)-fuzzy generalized bi-ideals of ordered semigroups. The important milestone of the present paper is to link ordinary generalized bi-ideals and (${\in},{\in}{\vee}\bar{q}_k$)-fuzzy generalized bi-ideals. Moreover, different classes of ordered semi-groups such as regular and left weakly regular ordered semigroups are characterized by the properties of this new notion. Finally, the upper part of a (${\in},{\in}{\vee}\bar{q}_k$)-fuzzy generalized bi-ideal is defined and some characterizations are discussed.

• 한국학교보건학회지
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• 제3권2호
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• pp.63-87
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• 1990

The purpose of this study was to investigate the performance rate of regular health instruction by school nurses and its related factors. These data were collected by questionnaire in Mar. 1990. Total 986 school nurses who have been working primary, secondary schools in Seoul were given the questionnaire, and 672 school nurses' respectively, were finally analyzed. Analysis of the data was done utilizing SPSS/PC+for percentage, frequency, mean, $X^2$-test, t-test, ANOVA, correlation, regression. The major findings of this study were as follows : 1. Thc performance rate of regular health instruction by school nurses was 77.7% of 552 respondents. 2. The school nurses in primary school(87.0%) were more likely to perform regular health instruction than the school nurses in secondary school (63.8%). 3. The teachers of regular health instruction were more likely to display favorable attitudes toward need of health instruction. The school level was not statistically significant(P>0.05). 4. The evidence from the data analysis supported the proposition that the teachers of regular health instruction had more positive attitude toward the establishment of health subject(80.3%). The school level was statistically significant(P<0.05). 5. The school principal was a highly significant factor as it affected the performance rate of regular health instruction by school nurses. The school level was statistically significant(P<0.001). 6. The length of past career, the degree of self confidence on health instruction, the need of health instruction did affect the performance rate of regular health instruction by school nurses. On the basis of the above mentioned, so as for regular health instruction of school to be activated more throughly, regular class must be introduced in the form of establishment of health subject, enhancement of quality on the part of school nurses, made and various methods for enhancing perception toward the regular health instruction on the part of school principal are to be carried out.