• Journal of the Korea Furniture Society
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• v.28 no.1
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• pp.80-87
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• 2017

As modern society attaches important to a value in mental aspect and characteristics of consumers who become diverse and individualistic, lighting design also changes closely with everyday life. This study suggests a new concept of indoor lighting design, combining natural objects with lattice and Korean paper, one of our representative traditional materials in lighting design used in everyday life. In particular, it was designed with aesthetic sense of traditional culture and Korean sentiment besides external effect and function by combining Korean paper with natural objects such as insect and plant, material that could be easily obtain around us. As a result, it is intended to enhance quality of life and pursue happiness by suggesting a new concept of lighting design which is modern, harmonizes with everyday life of modern humans who become individualistic, and can arouse sensibility, overcoming the limitations of traditional lighting in indoor lighting.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.4
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• pp.191-198
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• 2003

The generalized knapsack problem or gknap is the combinatorial optimization problem of optimizing a nonnegative linear function over the integral hull of the intersection of a polynomially separable 0-1 polytope and a knapsack constraint. The knapsack, the restricted shortest path, and the constrained spanning tree problem are a partial list of gknap. More interesting1y, all the problem that are known to have a fully polynomial approximation scheme, or FPTAS are gknap. We establish some necessary and sufficient conditions for a gknap to admit an FPTAS. To do so, we recapture the standard scaling and approximate binary search techniques in the framework of gknap. This also enables us to find a weaker sufficient condition than the strong NP-hardness that a gknap does not have an FPTAS. Finally, we apply the conditions to explore the fully polynomial approximability of the constrained spanning problem whose fully polynomial approximability is still open.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.441-448
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• 2007

Heart rate variability (HRV) in electrocardiogram (ECG) is an important index for understanding the health status of heart and the autonomic nervous system. Most HRV analysis approaches are based on the proper heart rate (HR) data. Estimation of heart rate is thus a key process in the HRV study. In this paper, we report an innovative method to estimate the heart rate. This method is mainly based on the concept of periodicity transform (PT) and instantaneous period (IP) estimate. The method presented is accordingly called the "PT-IP method." It does not require ECG R-wave detection and thus possesses robust noise-immune capability. While the noise contamination, ECG time-varying morphology, and subjects' physiological variations make the R-wave detection a difficult task, this method can help us effectively estimate HR for medical research and clinical diagnosis. The results of estimating HR from empirical ECG data verify the efficacy and reliability of the proposed method.

• Journal of the Korean Professional Engineers Association
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• v.33 no.2
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• pp.62-67
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• 2000

The trouble rank of business management of the small-medium manufacturing enterprises in Korea is constituted by that average 28.6% of production management in the worst trouble of business management from 1982 to 1999. The status of production management approaching problem is analyzed for Korean small-medium manufacturing enterprises and it us checked productivity improvement and requirement facts impede productivity improvement. It is expected to contribute much productivity improvement through a new established model of production management system and technique or tool for small-medium manufacturing enterprises in Korea.

• Journal of the Ergonomics Society of Korea
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• v.22 no.4
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• pp.59-78
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• 2003

Most regression models of anthropometric variables use stature and/or weight as regressors; however, these 'flat' regression models result in large errors for anthropometric variables having low correlations with the regressors. To develop more accurate regression models for anthropometric variables, this study proposed a method to estimate anthropometric variables in a hierarchical manner based on the relationships among the variables and a process to develop and improve corresponding regression models. By applying the proposed approach, a hierarchical estimation structure was constructed for 59 anthropometric variables selected for the occupant package design of a passenger car and corresponding regression models were developed with the 1988 US Army anthropometric survey data. The hierarchical regression models were compared with the corresponding flat regression models in terms of accuracy. As results, the standard errors of the hierarchical regression models decreased by 28% (4.3mm) on average compared with those of the flat models.

• Journal of the Korean Home Economics Association
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• v.28 no.3
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• pp.87-103
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• 1990

The purpose of this study is to provide basis data to understand the urban housewives' assets management behavior. The result can be summarized as follows: 1. The more urban housewives were educated, the more they were satisfied with methods of assets management. So it turned out that the educational improvement of husbands and wives brought forth the satisfaction of their lives. From this result, we can conclude that more improved education is essential to us. 2. Specifically, age is an important factor of the reasons of assets management. Among housewives below 40 years old. the preparation for purchasing durable goods and more leisure was the main reason for assets management. Among housewives from 40 to 50, the preparation for expenditures of education and marriage of their children was the main reason. Among housewives above 50, the preparation for their retirement was the main reason. As results, we can notice that they don't make a long-range plan positively but they usually prepare expenditures for their seasonable needs. So we have to emphasize on educating them to make a long-range plan.

• ETRI Journal
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• v.28 no.1
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• pp.17-30
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• 2006

In time division duplex (TDD) code division multiple access (CDMA) systems, chip-synchronous transmission in the uplink is obtainable, thus leading to free multiple access interference in flat Rayleigh fading channels plus additive white Gaussian noise. This motivates us to develop a novel cooperative transmission strategy that allows single-antenna devices to benefit from spatial diversity using orthogonal signature sequences. The proposed cooperation is applicable to many digital modulation methods and achieves the fullest diversity level, low implementation complexity, and a full data rate. Closed-form bit-error-rate expressions were also derived and compared to simulation results in order to evaluate its validity. A variety of numerical results demonstrated the cooperation's superiority over single transmission under the same transmit power constraint.

• Journal of Dairy Science and Biotechnology
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• v.25 no.2
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• pp.21-28
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• 2007

Recently, the field of microbiology has been transformed by huge increasing number of publicly available whole-genome sequences. This sequence information has significantly enhanced our understanding of the physiology, genetics, and evolutionary development of bacteria. Among the gastrointestinal microorganisms, bifidobacteria represent the most important human commensals because of their contribution to maintaining a balanced gastrointestinal tract microbiota. In recent years bifidobacteria have drawn much scientific attention due to their use as live bacteria in numerous food products with various health-related claims. For this reason, these bacteria constitute a growing area of interest with respect to genomics, molecular biology, and genetics. Recent genome sequencing of a number of bifidobacterial species has allowed access to the complete genetic make-up of these bacteria. This review will focus how genomic data has allowed us to understand bifidobacterial evolution, while also revealing genetic functions that explains their presence in the particular ecological environment of the gastrointestinal tract.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.1
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• pp.27-38
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• 1992

The paper presents a digital speed control approach of induction motor systems by using a digital redesign method and adopting a well known 2nd order model as the system model equation. The basic concept using the modeling equation is induced from the control theory stand point such that we can describe usually the motor system connected by inverter, generator and load etc. just as a mechanical system to be controlled. The concept does not demand us the complicated vector-based modeling equation adopted in the traditional methods for the speed control of induction motor. The effectiveness of the servo control system composed by the above mentioned design concept is illustrated by the experimental results in the presence of step reference change and generator load variation. It is observed from the experimental results that the steady state error of the experimental set up becomes zero after some regulation time and the induction motor system is robust in spite of reference signal change and load variation of generator.

• Journal of the Korean Mathematical Society
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• v.47 no.1
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• pp.17-28
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• 2010

In this paper we deal with linear chance-constrained optimization problems, a class of problems which naturally arise in practical applications in finance, engineering, transportation and scheduling, where decisions are made in presence of uncertainty. After giving the deterministic equivalent formulation of a linear chance-constrained optimization problem we construct a conjugate dual problem to it. Then we provide for this primal-dual pair weak sufficient conditions which ensure strong duality. In this way we generalize some results recently given in the literature. We also apply the general duality scheme to a portfolio optimization problem, a fact that allows us to derive necessary and sufficient optimality conditions for it.