• Journal of KIISE:Software and Applications
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• v.26 no.9
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• pp.1095-1104
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• 1999

객체지향 시스템의 개발은 클래스를 통해서 이루어진다. 즉, 문제 영역에 존재하는 중요한 대상 또는 개념을 클래스로 모델링하고, 이로부터 생성된 객체들 사이의 메시지 교환을 통해서 시스템은 구축된다. 또한, 클래스는 정보 은닉을 제공함으로써, 객체지향 시스템의 재사용성과 유지보수성에 상당한 기여를 한다. 그러나, 설계 단계에서 실세계의 대상을 부적절하게 모델링하거나, 또는 유지보수 단계에서 클래스에 무분별한 변경을 가하는 경우 클래스의 품질은 악화될 수 있고, 이는 결국 시스템을 유지보수 하거나 확장하는데 상당한 장애를 초래한다.응집도는 모듈의 구성 요소들 사이의 연관성 정도를 나타내는 척도로서 전통적으로 모듈의 품질을 평가하기 위한 기준으로 사용되어 왔다. 이 논문에서는 클래스의 품질을 평가하는 방법으로서의 클래스 응집도를 제안한다. 즉, 클래스가 실세계의 대상을 적절하게 모델링한다면, 그 구성요소들 사이에 밀접한 관련이 있고 결국 높은 응집도를 가지게 될 것이다. 반대로 실세계의 대상에 대한 적절한 모델이 아니라면, 그 클래스의 구성 요소들 사이에는 밀접한 관련성이 없을 것이고 따라서 낮은 응집도를 보일 것이다.Abstract Object-oriented systems are developed by means of classes; that is, classes captures the essential entities or concepts in the problem domain, and the system is embodied by the interactions of objects instantiated from the classes. In addition to the basic units of object-oriented systems, classes serves as the units of encapsulation, which considerably promote the modifiability and the extensibility of them. However, improper modeling in the design phase or uncontrolled changes during the maintenance phase can degrade the quality of classes, which leads to systems cumbersome to maintain and extend.Cohesion refers to the degree of connectivity among the elements of a single module, and is being used as a factor which characterizes the quality of a module. In this paper, we propose a new cohesion metric for assessing the quality of classes. If a class captures properly the essential features of objects, the members of the class surely have strong relationship among them. On the contrary, the poor relationship among class members can indicate that the class is not a proper model of objects.

• Korean Journal of Optics and Photonics
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• v.24 no.6
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• pp.311-317
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• 2013

It was reported in Nature and the Wall Street Journal on June 20th, 2012 that scientists at Duke university have developed a gigapixel camera, capable of over 1,000 times the resolution of a normal camera. According to the reports, this super-resolution camera was motivated by the need of US military authorities to surveil ground and sky. We notice the ripple effect of this technology has spread into the area of national defense and industry, so that this research has started to realize the super-resolution camera as a frontier research topic. As a result, we can understand the optical structure of a super-resolution camera's lens system to be composed of a front, monocentric objective of a single lens plus 98 rear, multiscale camera lenses. We can also obtain the numerical ranges of specification factors related to the optical structure, such as the diameter of the aperture, and the focal length.

• Industrial Engineering and Management Systems
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• v.11 no.3
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• pp.233-240
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• 2012

The implementation of business process management (BPM) systems in large number of business organizations transforms BPM system into such a level of maturity and tends to collect large repositories of business process (BP) models. This issue encourages BP flexibility that leads to a large number of process variants derived from the same model, but differing in structure, to be stored in the large repositories of BP models. Therefore, the repositories may include thousands of activities and related business objects with variation of requirements and quality of service. It is a common practice to customize processes from reference processes or templates in order to reduce the time and effort required to design and deploy processes on all levels. In order to address redundancy and underutilization problems, a generic process model, called as reference BP, is absolutely necessary to cover the best of process variants. This study aims to develop multiple-objective business process genetic algorithm (MOBPGA) to find a set of non-dominated (Pareto) solutions of business reference model to enhance conventional approach which considered only a single objective on creating BP reference model by using proximity score measurement. A mixed-integer linear program is constructed to evaluate performance of the proposed MOBPGA on small-scale problems by using standard measures for multiple-objective techniques. The results will show the viability of applying MOBPGA in terms of simultaneously maximizing proximity score measurement, minimizing total duration, and total costs of the selected reference model.

• Geomechanics and Engineering
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• v.32 no.3
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• pp.255-270
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• 2023

One of the main parameters that affect the design of suction caisson-supported offshore structures is uplift behavior. Pull-out of suction caissons is profoundly utilized as the offshore wind turbine foundations accompany by a tensile resistance that is a function of a complex interaction between the caisson dimensions, geometry, wall roughness, soil type, load history, pull-out rate, and many other parameters. In this paper, a parametric study using a 3-D finite element model (FEM) of a single offshore suction caisson (SOSC) surrounded by saturated soil is performed to examine the effect of some key factors on the tensile resistance of the suction bucket foundation. Among the aforementioned parameters, caisson geometry and uplift loading as well as the difference between the tensile resistance and suction pressure on the behavior of the soil-foundation system including tensile capacity are investigated. For this purpose, a full model including 3-D suction caisson, soil, and soil-structure interaction (SSI) is developed in Abaqus based on the u-p formulation accounting for soil displacement (u) and pore pressure, P.The dynamic responses of foundations are compared and validated with the known results from the literature. The paper has focused on the effect of geometry change of 3-D SOSC to present the soil-structure interaction and the tensile capacity. Different 3-D caisson models such as triangular, pentagonal, hexagonal, and octagonal are employed. It is observed that regardless of the caisson geometry, by increasing the uplift loading rate, the tensile resistance increases. More specifically, it is found that the resistance to pull-out of the cylinder is higher than the other geometries and this geometry is the optimum one for designing caissons.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.48-57
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• 2020

MCU used in applications such as wireless chargers and USB type-C require MTP memory with a small cell size and a small additional process mask. Conventional double poly EEPROM cells are small in size, but additional processing masks of about 3 to 5 sheets are required, and FN tunneling type single poly EEPROM cells have a large cell size. In this paper, a 110nm MTP cell using a vertical PIP capacitor is proposed. The erase operation of the proposed MTP cell uses FN tunneling between FG and EG, and the program operation uses CHEI injection method, which reduces the MTP cell size to 1.09㎛2 by sharing the PW of the MTP cell array. Meanwhile, MTP memory IP required for applications such as USB type-C needs to operate over a wide voltage range of 2.5V to 5.5V. However, the pumping current of the VPP charge pump is the lowest when the VCC voltage is the minimum 2.5V, while the ripple voltage is large when the VCC voltage is 5.5V. Therefore, in this paper, the VPP ripple voltage is reduced to within 0.19V through SPICE simulation because the pumping current is suppressed to 474.6㎂ even when VCC is increased by controlling the number of charge pumps turned on by using the VCC detector circuit.

• Journal of Photoscience
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• v.9 no.2
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• pp.66-69
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• 2002

Zinc chlorin 1 possessing tertiary 3$^1$_hydroxy and 13$^1$-oxo groups was synthesized as a model for the antenna chlorophylls of photosynthetic green bacteria. Self-aggregation of 1 in nonpolar organic solvents was examined and compared to 2 and 3 possessing a secondary and primary 3$^1$_hydroxy group, respectively. Zinc chlorin 1 self-aggregated in I％(v/v) CH$_2$Cl$_2$-hexane to form oligomers and showed a red-shifted Qy maximum at 704 nm compared to the monomer (648 nm in CH$_2$CI2$_2$). This red-shift is larger than that of 3$^1$S-2 (648 to 697 nm) and comparable to that of3$^1$R-2 (648 to 705 nm), but smaller than that of 1 (648 to 740 nm), indicating that while a single 3$^1$-methyl group (primary to secondary OH) suppressed tight and/or extended aggregation, the additional 3$^1$-methyl group (secondary to tertiary OH) did not further suppress aggregation. The relative stability of the aggregates was in the order 3> 3$^1$R-2∼ 1 > 3$^1$S-2 as determined by visible spectral analyses. Molecular modeling calculations on oligomers of zinc chlorins 1, 3$^1$ R-2 and 3 gave similar well-ordered energy-minimized structures, while 3 stacked more tightly than 3$^1$ R- 2 and 1. In contrast, 3$^1$S-2 gave a relatively disordered (twisted) structure. The calculated oligomeric structures could explain the visible spectral data of 1-3 in nonpolar organic solvents. Moreover, self- aggregation of synthetic zinc 13$^1$_oxo-hlorins 4-6 possessing a 2-hydroxyethyl, 3-hydroxypropyl and 3- hydroxy-I-propenyl group at the 3-position in nonpolar organic solvents was discussed.

• Progress in Superconductivity and Cryogenics
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• v.22 no.3
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• pp.20-24
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• 2020

The purpose of this analytic study is to design and examine an efficient hydrogen liquefaction cycle by using a pre-cooler. The liquefaction cycle is primarily comprised of a pre-cooler and a refrigerator. The fed hydrogen gas is cooled down from ambient temperature (300 K) to the pre-cooling coolant temperature (either 77 K or 120 K approximately) through the pre-cooler. There are two pre-cooling methods: a single pre-coolant pre-cooler and a cascade pre-cooler which uses two levels of pre-coolants. After heat exchanging with the pre-cooler, the hydrogen gas is further cooled and finally liquefied through the refrigerator. The working fluids of the potential pre-cooling cycle are selected as liquid nitrogen and liquefied natural gas. A commercial software Aspen HYSYS is utilized to perform the numerical simulation of the proposed liquefaction cycle. Efficiency is compared with respect to the various conditions of the heat exchanging part of the pre-cooler. The analysis results show that the cascade method is more efficient, and the heat exchanging part of the pre-coolers should have specific UA ratios to maximize both spatial and energy efficiencies. This paper presents the quantitative performance of the pre-cooler in the hydrogen liquefaction cycle in detail, which shall be useful for designing an energy-efficient liquefaction system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1106-1113
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• 2005

This paper presents a dual-band mixer for multi-standards of IEEE 802.1la/b/g using a single local oscillator, so as to improve the defects of legacy systems. Those systems have duplicate local oscillators and mixers to handle dual band signals, increasing complexity of system and power loss. The proposed circuit shows 11.6 dB, 16.8 dB of conversion loss and 8.77 dBm, 12.5 dBm of IIP3(Input 3rd Intercept Point) for respective bands when the two RF inputs of 2.452 and 5.260 GHz are down-converted to the identical 356 MHz If frequency. The RF-LO isolations are measured 36 dB, 41 dB at each frequencies and over 50 dB of LO-IF isolations are achieved at all cases.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.75-82
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• 2004

Many researcher's efforts have made a significant advancement of space frame structure with various portion, and it becomes the most outsanding one of space structures. However, with the characteristics of thin and long term of spacing, the unstable behavior of space structure is shown by initial imperfection, erection procedure or joint, especially space frame structure represents more. This kind of unstable problem could not be set up clearly and there is a huge difference between theory and experiment. Moreover, the discrete structure such as space frame has more complex solution, this it is not easy to derive the formulation of design about space structure. In this space frame structure, the character of rise-span ratio or load mode is represented by the instability of space frame structure with initial imperfection, and snap-through or bifurcation might be the main phenomenon. Therefore, in this study, space frame structure which has a lot of aesthetic effect and profitable for large space covering single layer is dealt. And because that the unstable behavior due to variation of inner force resistance in the elastic range is very important collapse mechanism, I would like to investigate unstable character as a nonlinear behavior with a geometric nonlinear. In order to study the instability. I derive tangent stiffness matrix using finite element method and with displacement incremental method perform nonlinear analysis of unit space structure, star dome and 3-ring star dome considering rise-span $ratio(\mu}$ and load $ratio(R_L)$ for analyzing unstable phenomenon.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.4 s.346
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• pp.49-55
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• 2006

In this paper, a fault dictionary for fault locations is considered. The foremost problem in fault diagnosis is the size of the data. As circuits are large, the data for fault diagnosis increase to the point where they are impossible to be stored. The increased information makes it impossible to store the dictionary into storage media. In order to generate the dictionary, j.e. pass-fail dictionary some dictionaries store a portion of the information. The deleted data makes it difficult to diagnose fault models except single stuck-at fault. This paper proposes a new dictionary format. A new format makes a dictionary small size without deleting any informations.