• 전기의세계
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• 제23권1호
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• pp.73-78
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• 1974

Digital simulation algorithms and program for multimachine dynamic stability have been developed which represent the effects of machines much more complety than have been available previously. Emphasis is given to the savings of the memory spaces required, thus making it possible to use a small computer with limited capacity of core storage (without auxiliary storage). Both d- and q- aris quantities are fully represented, and the speed-governing and voltage-regulating system available are ertensive, thus allowing a very close approximation to any physical system. Facilities for dynamic and nonlinear loads are also included. The computational algorithms and program developed have been shown to be extensive and complete, and are very desirable features minimizing memory spaces for stability calculations. The capabilities have been demonstrated by several case studies for an actual power system of 44 generators, 22 loads and 33 buses. About 13-K words of memory spaces have been required for the case studies on the basis of two words per real variable and a word per integer variable.

• International Journal of Contents
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• 제10권2호
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• pp.67-73
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• 2014

With a population of around 237,424,363 in 33 provinces, Indonesia is one developing countries that needs an excellent School Management Information System (SMIS) to accomplish its educational mission. To reach the goal, it is necessary to know the rules, culture of school and related data prior to building the SMIS. This study is focused on the Indonesian National Education Standards. It is has nine standards that are described by the Regulation of Education Ministry. To manage the schools' organization, this paper aims to develop a SMIS based on the Indonesian National Education Standards by using ARIS(Architecture of Integrated Information System) to help schools run efficiently. The new system will be built using UML(Unified Modeling Language), this new system conforms to the education rules of the government. Finally, the conclusion and future research are described.

• 산업공학
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• 제14권4호
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• pp.348-355
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• 2001

This paper suggests a detailed design of APS(Advanced Planning & Scheduling) system using the DBR (Drum-Buffer-Rope) which is a finite capacity scheduling logic of TOC(Theory of Constraints). Our design is composed of four modules; Network, Buffer, Drum and Subordination. The Network module defines the Product Network which is built from BOM and routings. The Buffer module inserts the Buffers into the Product Network. The Drum module describes detail procedures to create Drum Schedule on the CCR(Capacity Constraint Resource). The Subordination module synchronizes all non-constraints to the constraints by determining the length of Rope. This design documented by ARIS.

• 한국초지조사료학회지
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• 제12권2호
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• pp.89-97
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• 1992

This experiment was attempted to investigate the effects of growing stage, cutting frequency and the level of nitrogen fertilization on the change of carbohydrate reserves in reed canarygrass(Pha1aris arundinacea L.). The results obtained were as follows: The amount of carbohydrate reserves appeared to markedly decrease up to critical level after the cutting in hot and dry weather season. During the growing stage, the amount of carbohydrate reserves decreased just after the cutting and also during the period of flourishing elongation of reed canarygrass. However, it began to increase sharply from the end of September for wintering. Two cutting system showed the highest mean value(19.53 %) of carbohydrate reserves and those of three, five and four cutting system was 15.32 %. 14.73 %, and 14.60 % respectively. Reed canarygrass with no nitrogen fertilization resulted in 17.17% of carbohydrate reserve, however there was no singificant difference among various levels of nitrogen fertilization. In respect of regrowth. 3 cutting system showed the most effective cutting frequency, however 4 or 5 cutting system had a decreasing tendency of regrowth.

• 한국농공학회지
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• 제42권2호
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• pp.78-85
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• 2000

The moment equations of the concentration distribution for the multi-region model are derived using the method of moment. The method originally devised by Aris is to obtain the concentration moments satisfying a given PDE (Partial Differential Equation. The method of moment is used to obtain the first five moments (0th to 4to) that satisfy the model PDE. Each moment of the concentration distribution for the model equation is plotted for the dimensionless time and gave similar results except the skewness and the kurtosis. The results of the analysis show the physical meaning of each moment. The comparisons with the number of regions or the global interaction coefficient give a possibility to determine the parameters of the multi-region model with the analytical concepts.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.545-562
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• 2023

In this work, superharmonic and subharmonic resonance of rotating stiffened FGM truncated conical shells exposed to harmonic excitation in a thermal environment is investigated. Utilizing classical shell theory considering Coriolis acceleration and the centrifugal force, the governing equations are extracted. Non-linear model is formulated employing the von Kármán non-linear relations. In this study, to model the stiffener effects the smeared stiffened technique is utilized. The non-linear partial differential equations are discretized into non-linear ordinary differential equations by applying Galerkin's method. The method of multiple scales is utilized to examine the non-linear superharmonic and subharmonic resonances behavior of the conical shells. In this regard, the effects of the rotating speed of the shell on the frequency response plot are investigated. Also, the effects of different semi-vertex angles, force amplitude, volume-fraction index, and temperature variations on the frequency-response graph are examined for different rotating speeds of the stiffened FGM truncated conical shells.

• Structural Engineering and Mechanics
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• 제20권2호
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• pp.191-207
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• 2005

Time delay exists inevitably in active control, which may not only degrade the system performance but also render instability to the dynamic system. In this paper, a novel active controller is developed to solve the time delay problem in flexible structures. By using the independent modal space control method, the differential equation of the controlled mode with time delay is obtained from the time-delay system dynamics. Then it is discretized and changed into a first-order difference equation without any explicit time delay by augmenting the state variables. The modal controller is derived based on the augmented system using the discrete variable structure control method. The switching surface is determined by minimizing a discrete quadratic performance index. The modal coordinate is extracted from sensor measurements and the actuator control force is converted from the modal one. Since the time delay is explicitly included throughout the entire controller design without any approximation, the system performance and stability are guaranteed. Numerical simulations show that the proposed controller is feasible and effective in active vibration control of dynamic systems with time delay. If the time delay is not explicitly included in the controller design, instability may occur.

• The Journal of Asian Finance, Economics and Business
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• 제7권12호
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• pp.809-818
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• 2020

This study aims to analyze the factors affecting the timeliness of cooperative financial reporting. The methods of measurement and accountability of financial statements must be timely, as it is critical information for making decision. Factors related to accounting information system problems such as timeliness of financial reporting, accounting information systems, teamwork, and internal control were identified in the study as a model. The method in this research is quantitative by taking survey data. The data were processed using SPSS 25, with a model test and partial test to produce a study to analyze the factors that affect the timeliness of cooperative financial reporting. The samples consisted of 60 cooperatives from the city of Tangerang, in Indonesia. The correspondents have published financial reports for each period of the current year and were a legal entity. Furthermore, primary data were collected by a questionnaire using a Likert scale and analyzed by multiple linear regression. The results showed that the Accounting Information System, Teamwork, and Internal Control had a positive and significant effect on the Timeliness of Financial Report Submission. Therefore, the cooperative that prepares financial reports in a timely manner has applied the principles of accountability and transparency.

• Journal of Electrical Engineering and Technology
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• 제3권1호
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• pp.43-51
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• 2008

Evolutionary Algorithms (EAs) cover all the applications involving the use of Evolutionary Computation in electronic system design. It is largely applied to complex optimization problems. EAs introduce a new idea for automatic design of electronic systems; instead of imagine model, ions, and conventional techniques, it uses search algorithm to design a circuit. In this paper, a method for automatic optimization of the digital circuit design method has been introduced. This method is based on randomized search techniques mimicking natural genetic evolution. The proposed method is an iterative procedure that consists of a constant-size population of individuals, each one encoding a possible solution in a given problem space. The structure of the circuit is encoded into a one-dimensional genotype as represented by a finite string of bits. A number of bit strings is used to represent the wires connection between the level and 7 types of possible logic gates; XOR, XNOR, NAND, NOR, AND, OR, NOT 1, and NOT 2. The structure of gates are arranged in an $m{\times}n$ matrix form in which m is the number of input variables.

• Environmental Engineering Research
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• 제22권1호
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• pp.61-74
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• 2017

This study investigated the effect of various cations ($Ca^{2+}$, $Mg^{2+}$, $Al^{3+}$, $Mn^{2+}$, $Zn^{2+}$) on the autoaggregation (AAg) and surface hydrophobicity (SHb) of three different bacteria (Brevibacillus panacihumi strain (ZB1), Lysinibacillus fusiformis strain (ZB2) and Enterococcus faecalis strain (ZL)) using a 2-level factorial design. The AAg ratio was measured from the changes in the absorbance of the media. Results show that ZB2 had maximum AAg for the three bacteria investigated. A microscopic clustering of cells was observed when $Ca^{2+}$ was added to ZB2. The AAg was in the range of 62%, 58% and 34% for ZB2, ZB1 and ZL, respectively and correlated to the SHb. The aggregation and SHb of the microbial cells increased with increasing ionic strength due to the repulsive steric or overlap forces between the polymer covered surfaces. $Ca^{2+}$ demonstrated a more significant effect on aggregation and SHb of microbial cells due to an attractive binding force.