• Food Science and Biotechnology
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• v.16 no.5
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• pp.691-709
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• 2007

Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. However, inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance are causing a major limitation for their industrial use. By the way, recent advent of nanocomposite technology rekindled interests on the use of natural biopolymers in the food packaging application. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased mechanical strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have huge potential for application in the active food packaging industry. In this review, recent advances in the preparation and characterization of natural biopolymer-based nanocomposite films, and their potential use in food packaging applications are addressed.

• Journal of Ocean Engineering and Technology
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• v.18 no.2
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• pp.46-51
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• 2004

Natural frequencies of the transverse vibration of beams with step change in cross-section are obtained by using the asymptotic closed form solution. This closed form solution is found by using WKB method under the assumption of slowly varying properties, such as mass, cross-section, tension etc., along the beam length. However, this solution is found to be still very accurate even in the case of large variation in cross-section and tension. Therefore, this result can be easily applied to many engineering problems.

• Clinical and Experimental Pediatrics
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• v.51 no.2
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• pp.122-128
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• 2008

Roughly one third of medical problems in children are related to the musculoskeletal system. Most of these problems are common and can be precisely diagnosed. For these problems, nonoperative treatment or reassurance can be given by the pediatrician. Occasionally, a problem needs surgical treatment, but a precise diagnosis must be made. There is little agreement about what types of orthopedic problems a primary care pediatrician should understand in order to effectively care for children. Many pediatric residencies lack an organized teaching curriculum that effectively covers these topics or that includes a required pediatric orthopedic rotation. In this article the authors delineate pediatric orthopedic problems that require recognition and urgent surgical treatment and are relatively common, but have different treatment options (observation, conservative treatment, and surgery) depending on their natural history. Whenever possible, the diagnosis should be made before a decision to refer is made. An accurate diagnosis allows the pediatrician to discuss the natural history of the condition properly. Referral to the wrong specialty can needlessly generate expensive tests and further delay in treatment or generate inappropriate treatment. The parents can be reassured rather than waiting to hear the same information from another physician. In particular, orthopedic problems are known to generate pressure from the parents to seek specialty consultation for reassurance. It is important to communicate to the specialist that the reason for the referral is for parental reassurance rather than for further work-up or treatment. After a proper diagnosis, communication directly between the pediatrician and the appropriate specialist can often avoid an unnecessary referral, and avoid unnecessary tests. The authors reviewed our experience at our outpatient clinic over last 1 year and found that it is useful to classify conditions as common or uncommon, and whether they require surgical or nonsurgical treatment. Many conditions fall in between. The following is a discussion of some of these more important or common conditions.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.91-100
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• 2016

In this research, emergency vehicle dispatching problems faced with in the wake of massive natural disasters are considered. Here, the emergency vehicle dispatching problems can be regarded as a single machine stochastic scheduling problems, where the processing times are independently and identically distributed random variables, are considered. The objective of minimizing the expected number of tardy jobs, with distinct job due dates that are independently and arbitrarily distributed random variables, is dealt with. For these problems, optimal static-list policies can be found by solving corresponding assignment problems. However, for the special cases where due dates are exponentially distributed random variables, using a proposed dynamic programming approach is found to be relatively faster than solving the corresponding assignment problems. This so-called Pivot Dynamic Programming approach exploits necessary optimality conditions derived for ordering the jobs partially.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.60-62
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• 2011

The presentation raises some elements related to marine traffic safety in Sai Gon-Vung Tau fairway with the aim that it could be a basis for further analysis to find out a solution for improving marine traffic safety in the fairway, the most important fairway in the South part of Vietnam.

• Journal of applied mathematics & informatics
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• v.35 no.3_4
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• pp.399-411
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• 2017

We first provide the linear operator equations corresponding to the Tikhonov regularization image denoising problems with different regularization terms, and then we propose how to choose Kronecker product preconditioners which are required for accelerating the $G{\ell}$-PCG method. Next, we provide how to apply the $G{\ell}$-PCG method with Kronecker product preconditioner to the linear operator equations. Lastly, we provide numerical experiments for image denoisng problems to evaluate the effectiveness of the $G{\ell}$-PCG with Kronecker product preconditioner.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.531-540
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• 2018

We first show how to construct the linear operator equations corresponding to Tikhonov regularization problems for solving image deblurring problems with nearly separable point spread functions. We next propose a Kronecker product preconditioner which is suitable for the global PCG method. Lastly, we provide numerical experiments of the global PCG method with the Kronecker product preconditioner for several image deblurring problems to evaluate its effectiveness.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.1
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• pp.59-64
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• 2007

In this paper, we will introduce the generalized operator equlibrium problem and generalized operator quasi-equlibrium problem which generalize operator equlibrium problem due to Kazmi and Raouf into multi-valued and quasi-equlibrium problems. Using a Park's fixed point theorem, we will prove a new existence theorem on generalized operator equlibrium problem which serves as a basic existence theorem for various kinds of nonlinear problems.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.139-148
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• 2002

When the natural villages in Jeju province are incorporated into the district of city planning, they are considered to be a small-scale residential districts. Therefore, a garden city should be planned that considers the characteristics of the villages to implement an appropriate street system, to use the area effectively, and to harmonize the villages with the surrounding communities. There have been an especially large number of problems with the street system in the city of Seogwipo, which was notified as the area of natural settlement. This study analyzes the problems inherent in street planning and the present condition of roads whose construction has been postponed for a long time due to several problems including an inappropriately planned street system. Based on the research of various documents, a practical street system has been investigated. Most of the residents in natural settlement units demand use of the continued the existing roads as well as the implementation of an effective street system. They ask for street planning under which the involved construction would take only a short period of time and would result in only minimal damage to their existing properties. Therefore, the street system should be planned so as to preserve the nature-friendly features of natural settlements, their surroundings and tourism resources. Even after streets hwve been planned and their completion you has been established, the plan should be continuously evaluated, analyzed and compared with other alternatives. The street plan should continuously incorporate improvement measures which would satisfy various aspects of the street system including land use, traffic demand, and future population demands. Both the amount of money to be invested and economical efficiency should be considered for street planning since the street system has a great impact on many industries. Unnecessary costs related to excessive road construction should be avoided. The street network plan should also include the complete evaluation of the natural topography as well as the surrounding. Considering these views, the data concerning the current condition of the city and the related investigation play an important role in establishing a street plan. However, the investigation of future construction plans by the city is as of yet at a very early stage. Therefore, there is an urgent need for the investigational study of the current city development plans. The street system for the natural settlement area should be established only after the thorough investigation of all aspects of street planning. In addition, the plan should be flexible enough to consider the characteristics of Jeju.

• International Journal of Computer Science & Network Security
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• v.21 no.6
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• pp.47-53
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• 2021

The article deals with the problems of application of microwave methods in systems of geoecological monitoring of natural environments and resources of the agro-industrial complex. It is noted that the methods of microwave radiometry make it possible, by the power of the measured intrinsic radio-thermal radiation of the atmosphere, when solving inverse problems using empirical and semi-empirical models, to determine such parameters of the atmosphere as thermodynamic temperature, humidity, water content, moisture content, precipitation intensity, and the presence of different fractions of clouds.In addition to assessing the meteorological parameters of the atmosphere and the geophysical parameters of the underlying surface based on the data of microwave radiometric measurements, it is possible to promptly detect and study pollution of both the atmosphere and the earth's surface. A technique has been developed for the analysis of sources of measurement error and their numerical evaluation, because they have a significant effect on the accuracy of solving inverse problems of reconstructing the values of the physical parameters of the probed media.To analyze the degree of influence of the limited spatial selectivity of the antenna of the microwave radiometric system on the measurement error, we calculated the relative measurement error of the ratio of radio brightness contrasts in two angular directions. It has been determined that in the system of geoecological monitoring of natural environments, the effect of background noise is maximal with small changes in the radiobrightness temperature during angular scanning and high sensitivity of the receiving equipment.