• Journal of Bio-Environment Control
• /
• 제9권4호
• /
• pp.201-206
• /
• 2000

A certain system to overcome high temperature should be introduced for the stable year-round cultivation in greenhouses. There are efficient methods to overcome high temperature such as ventilation system with shading screen, fan and pad system with screen, and fog system with screen. This study was carried out to find a means to determine the capacity of such system. Heat balance equations for each system were established and verified by experimental results. The calculated ventilation rates from heat balance equations showed a good agreement with the measured ones. The evapotranspiration coefficient was the most important parameter affecting the ventilation requirement among input parameter affecting the ventilation requirement among input parameters except weather data. When the evaportanspiration coefficient increased 1%, the ventilation requirement decreased 1.3%. Therefore the data of evapotranspiration coefficient should be accumulated by various experiments, and then design standards and selection guidelines should be provided. The simulation results for same design conditions shown that air exchanges requirement and evaporating water of fan and pad system were 5.1∼7.7% and 6.8∼9.3% larger than those of fog system, respectively.

• Korean Journal of Agricultural and Forest Meteorology
• /
• 제18권1호
• /
• pp.42-54
• /
• 2016

It is highly anticipated that warming temperature resulting from global climate change will affect the phenological pattern of kiwifruit, which has been commercially grown in Korea since the early 1980s. Here, we present the potential impacts of climate change on the variations of flowering day of a gold kiwifruit cultivar, Haegeum, in the Jeonnam Province, Korea. By running six global climate models (GCM), the results from this study emphasize the uncertainty in climate change scenarios. To predict the flowering day of kiwifruit, we obtained three parameters of the 'Chill-day' model for the simulation of Haegeum: $6.3^{\circ}C$ for the base temperature (Tb), 102.5 for chill requirement (Rc), and 575 for heat requirement (Rh). Two separate validations of the resulting 'Chill-day' model were conducted. First, direct comparisons were made between the observed flowering days collected from 25 kiwifruit orchards for two years (2014-15) and the simulated flowering days from the 'Chill-day' model using weather data from four weather stations near the 25 orchards. The estimation error between the observed and simulated flowering days was 5.2 days. Second, the model was simulated using temperature data extracted, for the 25 orchards, from a high-resolution digital temperature map, resulting in the error of 3.4 days. Using the RCP 4.5 and 8.5 climate change scenarios from six GCMs for the period of 2021-40, the future flowering days were simulated with the 'Chill-day' model. The predicted flowering days of Haegeum in Jeonnam were advanced more than 10 days compared to the present ones from multi-model ensemble, while some individual models resulted in quite different magnitudes of impacts, indicating the multi-model ensemble accounts for uncertainty better than individual climate models. In addition, the current flowering period of Haegeum in Jeonnam Province was predicted to expand northward, reaching over Jeonbuk and Chungnam Provinces. This preliminary result will provide a basis for the local impact assessment of climate change as more phenology models are developed for other fruit trees.

• Bulletin of the Korean Space Science Society
• /
• 한국우주과학회 2011년도 한국우주과학회보 제20권1호
• /
• pp.30.1-30.1
• /
• 2011

We present construction of 3D Earth optical Model for in-orbit performance prediction of L1 halo orbiting earth remote sensing instrument; the Albedo Monitor and Radiometer (Amon-Ra) using Integrated Ray Tracing (IRT) computational technique. The 3 components are defined in IRT; 1) Sun model, 2) Earth system model (Atmosphere, Land and Ocean), 3)Amon-Ra Instrument model. In this report, constructed sun model has Lambertian scattering hemisphere structure. The atmosphere is composed of 16 distributed structures and each optical model includes scatter model with both reflecting and transmitting direction respond to 5 deg. intervals of azimuth and zenith angles. Land structure model uses coastline and 5 kinds of vegetation distribution data structure, and its non-Lambertian scattering is defined with the semi-empirical "parametric kernel method" used for MODIS (NASA) missions. The ocean model includes sea ice cap with the sea ice area data from NOAA, and sea water optical model which is considering non-Lambertian sun-glint scattering. The IRT computation demonstrate that the designed Amon-Ra optical system satisfies the imaging and radiometric performance requirement. The technical details of the 3D Earth Model, IRT model construction and its computation results are presented together with future-works.

• Industrial Engineering and Management Systems
• /
• 제13권4호
• /
• pp.432-441
• /
• 2014

As the business model is receiving considerable attention these days, the ability to collect business model related information has become essential requirement for a company. The annual report is one of the most important external documents which contain crucial information about the company's business model. By investigating business descriptions and their future strategies within the annual report, we can easily analyze a company's business model. However, given the sheer volume of the data, which is usually over a hundred pages, it is not practical to depend only on manual extraction. The purpose of this study is to complement the manual extraction process by using text mining techniques. In this study, the text mining technique is applied in business model concept extraction and business model evolution analysis. By concept, we mean the overview of a company's business model within a specific year, and, by evolution, we mean temporal changes in the business model concept over time. The efficiency and effectiveness of our methodology is illustrated by a case example of three companies in the US video rental industry.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• 제9권5호
• /
• pp.169-174
• /
• 2009

In this paper, We define convert rules objects and relation presented in object model to the state and operation domain in formal specification. we implement simulation tool in order to verification method of formal specification and to consistency verified model between user's requirement. It is possible to select the suitable model and reduce the costs and efforts on software development.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.561-569
• /
• 2017

Power converter design requires simulation accuracy. In addition to the requirement of accurate models of power semiconductor devices, this paper highlights the role of considering a very good description of the converter circuit layout for an accurate simulation of its electrical behavior. This paper considers a simple experimental circuit including one switching cell where a MOSFET transistor controls the diode under test. The turn-off transients of the diode are captured, over which the circuit wiring has a major influence. This paper investigates the necessity for accurate modeling of the experimental test circuit wiring and the MOSFET transistor. It shows that a simple wiring inductance as the circuit wiring representation is insufficient. An adequate model and identification of the model parameters are then discussed. Results are validated through experimental and simulation results.

• IE interfaces
• /
• 제23권3호
• /
• pp.229-238
• /
• 2010

Virtual metrology (VM), a critical component of semiconductor manufacturing, is an efficient way of assessing the quality of wafers not actually measured. This is done based on a model between equipment sensor data (obtained for all wafers) and the quality characteristics of wafers actually measured. This paper considers principal component regression (PCR), partial least squares regression (PLSR), kernel PCR (KPCR), and kernel PLSR (KPLSR) as VM models. For each regression model, two cases are considered. One utilizes all explanatory variables in developing a model, and the other selects significant variables using the genetic algorithm (GA). The prediction performances of 8 regression models are compared for the short- and long-term etch process data. It is found among others that the GA-KPLSR model performs best for both types of data. Especially, its prediction ability is within the requirement for the short-term data implying that it can be used to implement VM for real etch processes.

• IE interfaces
• /
• 제20권3호
• /
• pp.387-394
• /
• 2007

Numerous countries promote business programs to revitalize local economy, increase employment, and nurture high-tech industries. Recently, a number of business incubators have been established and operated with aims to adapt to changing environment and increase economic competitiveness in Korea. To give satisfactory results of governmental policy, the requirement to develop the evaluation model to support effective operations of business incubators using the objective and rational criteria is growing. The purpose of this study is to develop evaluation model in Business Incubator using Data Mining Process. We suggested the evaluation model of business incubator, 'Score-5 RS' consists of making evaluation factor process using weighted sum and 5-grade classification and analyzing process by Decision Tree algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 한국경영과학회 1998년도 추계학술대회 논문집
• /
• pp.289-293
• /
• 1998

Two reasons for the low success rate of the practical implementation of BPR are the lack of good models and consideration of information system development stage in a BPR project. This paper suggests an Integrated Business Process Model (IBPM), which incorporates two distinct but interrelated points of view: form and business process. By integrating the form model with the business process model, the IBPM has advantages in performing BPR projects; it helps to build the model, to analyze and redesign business processes, and to do requirement analysis of information systems. This paper also suggests a new BPR supporting tool, BRAWII(Business Reengineering Assistance Workbench version 2.0). BRAWIIsupports IBPM and manages full stages of BPR project. In the design of BRAWII, the linkage between results of a BPR project and requirements for information system development is considered.

• Journal of Institute of Convergence Technology
• /
• 제4권2호
• /
• pp.1-9
• /
• 2014

This paper examines feature-based reconstruction algorithm using feature-based modeling and based on topology optimization technology, which aims to achieve a minimal volume weight and to satisfy user-defined constraints such as stress, deformation related conditions. The finite element model after topology optimization allows us to remove some region of a solid model for predefined volume requirement. The stress or deformation distribution resulted from finite element analysis enables us to add some material to the solid model for a robust structure. For this purpose, we propose a feature-based redesign algorithm which inserts negative features to the solid model for material removal and positive features for material addition, and we introduce a bisection method which searches an optimal structure by iteratively applying the feature-based redesign algorithm. Several examples are considered to illustrate the proposed algorithms and to demonstrate the effectiveness of the present approach.