• Knowledge Management Research
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• v.22 no.4
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• pp.119-133
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• 2021

As a large amount of data is produced in each industry, a number of time series pattern prediction studies are being conducted to make quick business decisions. However, there is a limit to predicting specific patterns in nonlinear time series data due to the uncertainty inherent in the data, and there are difficulties in making strategic decisions in corporate management. In addition, in recent decades, various studies have been conducted on data such as demand/supply and financial markets that are suitable for industrial purposes to predict time series data of irregular random walk models, but predict specific rules and achieve sustainable corporate objectives There are difficulties. In this study, the prediction results were compared and analyzed using the Chaos analysis method for roulette data and financial market data, and meaningful results were derived. And, this study confirmed that chaos analysis is useful for finding a new method in analyzing time series data. By comparing and analyzing the characteristics of roulette games with the time series of Korean stock index future, it was derived that predictive power can be improved if the trend is confirmed, and it is meaningful in determining whether nonlinear time series data with high uncertainty have a specific pattern.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.2
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• pp.156-172
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• 2018

Recently, Korea suffered serious social conflicts between generations due to population aging. Anxiety about depletion of the National Pension Fund is one of the social problem to young generation, because of the uncertainty that they will not able to receive the pension they paid. At the same time, due to the high housing rent in Seoul metropolitan area, the demand for housing welfare and supply of public rental housing for young generation was increased. There are some opinions about using National Pension Fund to supplying public rental houses in the society. In this research, we were concentrated on finding the suitable areas for the public rental house using National Pension Fund. First, verifying the validity of the investment using National Pension Fund for the public rental housing was done. And spatial statistical methods were applied to explore the suitable areas for the public rental housing in Seoul metro area. Finally, this study divided young people into three groups and analyzed ways to supply public rental housing for each group in proper areas by their demand. This research's ultimate goals are mitigating the conflicts between the generations and achieving both profitability and publicness of National Pension Fund.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.151-162
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• 1997

Although modern versions of the traditional Von $Th{\ddot{u}}nen$ theory have contributed to a description of spatial organization in agriculture, they did not incorporate the market mechanism as an integral part of location theory. This deficiency has been indicated and new mathematical structure has been proposed elsewhere by the author. The closed model, which simultaneously considered a basic principle of supply and demand, exposed a computational complexity. Based on the problem, this study attempts to extend market mechanism in order to consider the influence of city (market) size in agricultural location theory. To theoretically explore the economic relationship in a location theory, this study simplifies agricultural activity as just two activities in one-dimensional spatial economy. The problem has been solved by equating total supply and demand of agricultural products, and then by determining each agricultural price from the relationship. All of the mathematical problems have been arranged in matrix form. First, the traditional model and closed model have been compared by quantitative comparative statics which provides the sensitivity test for each model. The results have shown that the traditional model shows a relatively excessive change in land use, besides the deficiency of a constant agricultural price. Second, the effects of the size of market town and its population increase were examined, using the closed model. In this case, the price of agricultural product is increased, and the land use is extended outward. This proves that locational rent is related to the expansion of land use. Third, environmental uncertainty was associated with the closed model, in order to further consider the difference of farmers attitude in strategic perspective. In this study, two extreme attitudes, which reflects the maximum average expected returns and the maximum guaranteed returns, were examined in their land use and their effects on the prices of agricultural products. It was shown that the two farmers attitudes can be interconnected with location theory. Due to the exogenous data, the differences in the area of land use and total quantities of agricultural products were not clearly shown in this study. However, it was shown that the land use pattern is very different. That is, maximum guaranteed return model reveals a mixed land use pattern around the market town. Basically, this study shows some spatial and economic implications related to Von $Th{\ddot{u}}nen$ model.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.1-1
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• 2016

Many of the world's large ecosystems are severely stressed due to population growth, water quality and quantity problems, vulnerability to flood and drought, and the loss of native species and cultural resources. Consequences of climate change further increase uncertainties about the future. These major societal challenges must be addressed through innovations in governance, policy, and ways of implementing management strategies. Science and engineering play a critical role in helping define possible alternative futures that could be achieved and the possible consequences to economic development, quality of life, and sustainability of ecosystem services. Science has advanced rapidly during the past decade with the emergence of science communities coalescing around 'Grand Challenges' and the maturation of how these communities function has resulted in large interdisciplinary research networks. An example is the River Experiment Center of KICT that engages researchers from throughout Korea and the world. This trend has been complemented by major advances in sensor technologies and data synthesis to accelerate knowledge discovery. These factors combine to allow scientific debate to occur in a more open and transparent manner. The availability of information and improved communication of scientific and engineering issues is raising the level of dialogue at the science-policy interface. However, severe challenges persist since scientific discovery does not occur on the same timeframe as management actions, policy decisions or at the pace sometimes expected by elected officials. Common challenges include the need to make decisions in the face of considerable uncertainty, ensuring research results are actionable and preventing science being used by special interests to delay or obsfucate decisions. These challenges are explored in the context of examples from the United States, including the California Bay-Delta system. California transfers water from the wetter northern part of the state to the drier southern part of the state through the Central Valley Project since 1940 and this was supplemented by the State Water Project in 1973. The scale of these activities is remarkable: approximately two thirds of the population of Californians rely on water from the Delta, these waters also irrigate up to 45% of the fruits & vegetables produced in the US, and about 80% of California's commercial fishery species live in or migrate through the Bay-Delta. This Delta region is a global hotspot for biodiversity that provides habitat for over 700 species, but is also a hotspot for the loss of biodiversity with more than 25 species currently listed by the Endangered Species Act. Understanding the decline of the fragile ecosystem of the Bay-Delta system and the potential consequences to economic growth if water transfers are reduced for the environment, the California State Legislature passed landmark legislation in 2009 (CA Water Code SS 85054) that established "Coequal goals of providing a more reliable water supply for California and protecting, restoring, and enhancing the Delta ecosystem". The legislation also stated that "The coequal goals shall be achieved in a manner that protects and enhances the unique cultural, recreational, natural resource, and agricultural values of the Delta as an evolving place." The challenges of integrating policy, management and scientific research will be described through this and other international examples.

• Information Systems Review
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• v.19 no.4
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• pp.1-25
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• 2017

Despite high uncertainty on financial return, firms have continuously increased their investment on technologies because they recognize the potential value of technology investment in terms of enhancing operational efficiency and sustaining competitive advantage. Notably, an individual technology investment pattern or strategy within an industry may ultimately lead to significant differences in business performance. Hence, we first categorized technology investment into traditional research and development investment and information technology investment. Afterward, we examined the effects of each pattern with combination of the two types of technology investment on business performance according to firm size and position in the supply chain through fuzzy-set qualitative comparative analysis. Data collected from 562 manufacturing firms in Korea were used in the analysis. Results showed that large-sized firms were slightly affected with microscopic patterns in their technology investments, whereas small firms were highly affected with their technology investment patterns and their positions in the supply chain. The findings implied that a small enterprise requires an appropriate technology investment strategy to achieve successful business outcomes.

• Journal of IKEEE
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• v.13 no.1
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• pp.41-48
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• 2009

This paper describes an implementation of the analog front end (AFE) incorporated with the image signal processing (ISP) unit in the SoC, dominating the performance of the CCD image sensor system. New schemes are exploited in the high-frequency sampling to reduce the sampling uncertainty apparently as the frequency increases, in the structure for the wide-range variable gain amplifier (VGA) capable of $0{\sim}36\;dB$ exponential gain control to meet the needed bandwidth and accuracy by adopting a new parasitic insensitive capacitor array. Moreover, the double cancellation of the black-level noise was efficiently achieved both in the analog and the digital domain. The proposed topology fabricated in a $0.35-{\mu}m$ CMOS process was proved in a full CCD camera system of 10-bit accuracy, dissipating 80 mA at 15 MHz with a 3.3 V supply voltage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4692-4697
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• 2014

A micro-grid including photovoltaic source and Li battery has been installed and operated for several years at the campus of USF and been used as a test bed. Photovoltaic power source has been strongly influenced by the location, weather and climate of the installed area. To compensate for the uncertainty of photovoltaic source's power output, a Li battery is connected directly to the photovoltaic source and supplies electric power to the grid. The Li battery is operated to supply power output to the grid according to the charging or discharging mode of the battery based on the average power output of the photovoltaic source, which is calculated from the monitored data for several years. The grid of the photovoltaic and Li battery system is operated as a severe loading condition and the operating characteristics of PV source and Li battery cells are analyzed in detail.

• Journal of Power System Engineering
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• v.17 no.3
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• pp.89-98
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• 2013

In this paper, the authors consider control system design problem of barge type surface vessel. It is based on the Dynamic Positioning System(DPS) design problem. The main role of barge ship is to carry and supply the materials to the floating units and other places. To carry out this job, it should be positioned in the specified area. Even though sometimes the thrust systems are installed on it, in general the mooring winch system with the rope is used. It may be difficult to compare the control performances of two types. But, if we consider this problem in point of usefulness, we can easily find out that the winch control system is more useful and applicable to the real field than the thrust control system except a special use. Therefore, in this paper we consider a single type mooring winch system and control system design problem in which accurate position control is needed. Because this result can be extended to the general type mooring system in which a number of winch are installed. At first, a mathematical model of winch is obtained and evaluated to verify the usefulness for control system design by experiment. Also, the disturbance model is extracted from experiment data to evaluate the strength of the uncertainty. Based on this results, the robust control system is designed and control performance is evaluated by simulation.

• Journal of Chest Surgery
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• v.30 no.9
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• pp.941-944
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• 1997

Pulmonary infarction is rarely diagnosed with certainty except at postmortem examination. Part of this uncertainty is because of the inability to distinguish between hemorrhage, congestive a electasis, and necrosis clinically and radiographically. The pathogenesis of pulmonary infarction is poorly understood. It is dif%cult to induce pulmonary infarction in animals by ligation of the arterial supply to the lung. Many factors seem to be important in its pathogenesis, in addition to congestive heart failure, malignant tumor, thrombophlebitis, chronic obstructive lung disease, nephrotic syndrome, and postopeiative state. However, pulmonary infarction have not been reported in association with chest trauma. We report a case of pulmonary infarction associated with fractures of right clavicle and multiple ribs. A 45-year-old male had admitted due to right chest pain and dyspnea, which developed after right chest trauma occurred at about 3 weeks ago. He was treated at local clinics under the diagnosis of fractures of right clavicle and ribs until the admission. Chest CT disclosed a huge mass with central low density in right upper lobe, and small masses were also seen on both l ng fields. Open lung biopsy resulted in negativity for the malignancy. Clinical symptoms and radiological findings were not improved by conservative treatment. Right upper lobectomy was done eventually. The final diagnosis was pulmonary infarction. And, the patient has been well after operation.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.9-10
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• 2001

Simulation has been evolved with the advance of computer and technique of modeling application systems. Early simulations were numerical analysis of engineering models known as continuous simulation, analysis of random events using various random number generators thus named as Monte Carlo simulation, iud analysis o(\\\\`queues which are prevalent in many real world systems including manufacturing, transportation, telecommunication. Discrete-event simulation has been used far modeling and analyzing the systems with waiting lines and inefficient delays. These simulations, either discrete-event, continuous, or hybrid, have played a key role in industrial age by helping to design and implement the efficient real world systems. In the information age which has been brought up by the advent of Internet, e-business has emerged. E-business, any business using Internet, can be characterized by the network of extended enterprises---extended supply and demand chains. The extension of value chains spans far reaching scope in business functions and space globally. It also extends to the individual customer, customer preferences and behaviors, to find the best service and product fit for each individual---mass customization. Simulation should also play a key role in analyzing and evaluating the various phenomena of e-business where the phenomena can be characterized by dynamics, uncertainty, and complexity. In this tutorial, applications of simulation to e-business phenomena will be explained and illustrated. Examples are the dynamics of new economy, analysis of e-business processes, virtual manufacturing system, digital divide phenomena, etc. Partly influenced by e-business, a new trend of simulation has emerged called agent-based simulation, Agent-based simulation is a technique of simulation using software agent that have autonomy and proactivity which are useful in analyzing and integrating numerous individual customer's behavior. One particular form of agent-based simulation is swarm. This tutorial concludes with the illustration of swarm or swarm Intelligence applied to various e-business applications, and future directions and implications of this new trend of simulation.