• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.82-88
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. There are two types of concentration optics for solar energy conversion. One is to use mirrors, and the other is to use Fresnel lenses. The gains that can be achieved with a Fresnel lens or a parabolic mirror are compared. The result showed the gains are comparable and the two configurations were developed competitively. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. A convex linear Fresnel lens to improve the concentration ratio and the efficiency is devised and flat linear Fresnel lens in thermal energy collection is utilized. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the 'grooves in case' has the better efficiency than that of 'grooves out case'. Based on the ray-trace results we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.506-512
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• 2018

The fine dust generated in the home and restaurant business occupies a low ratio of about 4% of the total fine dust emissions. However, at the foodservice business, the rate of change of the pollutant concentration is very high, so that the temporary fine dust concentration can be measured up to 60 times. The pollutants generated from non-industrial combustion plants consist of particulate fine dust and gaseous organic compounds. To remove these pollutants, cleaning dust collection system, which is an effective system for simultaneous removal of gaseous and particulate matter, is applied. This is a method of increasing the probability of diffusion capture of the Brownian motion by pressurized liquid injection method using the atomizing nozzle. The dust removal efficiency of the fine dust collecting system was analyzed by nozzle spraying air pressure condition and angle using the manufactured fine dust removing system. As a result, it was confirmed that the efficiency of removal of fine dust and gaseous organic compounds was more than 90%. The developed system is expected to be highly usable in the future because it can remove particulate dust from the existing plant hood system without any installation cost.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.3
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• pp.57-77
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• 2021

The identity of public libraries in Japan is a social education institution under the 「Social Education Act」 and the 「Library Act」. For these identities, the local government's board of education has operated and managed public libraries, and some have managed by the Management Outsourcing System to public organizations. Then, in 2003, the 「Local Autonomy Act」 was revised to introduce the Designated Manager System in form of administrative disposition, and expanded the scope of application to private institutions and organizations. As of the end of 2018, 18.0% of public libraries introduced the DMS, but the pros and cons surrounding it are sharply opposed. This study outlined the overall status of the DMS and the introduction of public libraries, and critically reviewed major issues. As a result, As a result, there was much controversy over the expected cost reduction, service improvement, employee professionalism, business continuity, and cooperation network establishment when DMS was introduced. The reasons were due to downsizing-based personnel management, contract-oriented employment, short periods of designation, lack of multiple competitive markets, and declining service capabilities of irregular workers. The public library is a knowledge and cultural infrastructure that enhances human values and social dignity based on faithful collection and active service, and is a local public goods that emphasizes non-exclusion and non-competitiveness. Given the increasing number of cases in which public libraries are recently contracting out to cultural foundations in Korea, DMS is not a fire across the river. We need to be wary of the possibility that Japan's unbearable institutional lightness will be applied to public libraries in Korea.

• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.543-550
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• 2020

Mosquitoes are globally distributed and important vectors for the transmission of many human diseases. Mosquito control is a difficult task and the cost of preventing mosquito-borne diseases is much lower than that for curing the associated diseases. Thus, chemical control remains the most effective tool for mosquito. Due to the long-term intensive use of insecticides to control mosquito vectors, resistance to most chemical insecticides has been reported. This study aimed to investigate the relationship between insecticide resistance and target site mutation of L1014 kdr and G119 ace alleles in 5 species/species group of mosquitoes (Aedes vexans, Ae. albopictus, Anopheles spp., Culex pipiens complex, and Cx. tritaeniorhynchus) obtained from 6 collection sites. For Anopheles spp., the proportion of mosquitoes with mutated alleles in L1014 was 88.4%, homozygous resistant genotypes were observed in 46.7%, and heterozygous resistant genotypes were observed in 41.8%. For the Cx. pipiens complex and Cx. tritaeniorhynchus species, homozygous resistant genotypes were found in 25.9% and 9.8%, respectively. However, target site mutation of L1014 in the Ae. vexans nipponii and Ae. albopictus species was not observed. Anopheles spp., Cx. pipiens complex, and Cx. tritaeniorhynchus mosquitoes were resistant to deltamethrin and chlorpyriphos, whereas Ae. vexans nipponii and Ae. albopictus were clearly susceptible. We also found a correlation between the resistance phenotype and the presence of the L1014 kdr and G119 ace mutations only in the Anopheles spp. population. In this study, we suggest that insecticide resistance poses a growing threat and resistance management must be integrated into all mosquito control programs.

• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.550-557
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• 2021

With the advent of the fourth industrial revolution, the interest in the internet of things (IoT) in manufacturing is growing, even at foundries. There are several types of process data that can be automatically collected at a foundry, but considerable amounts of process data are still managed based on handwriting for reasons such as the limited functions of outdated production facilities and process design based on operator know-how. In particular, despite recognizing the importance of converting process data into big data, many companies have difficulty adopting these steps willingly due to the burden of system construction costs. In this study, the field applicability of IoT-based devices was examined by manufacturing devices and applying them directly to the site of a centrifugal foundry. For the centrifugal casting process, the temperature and humidity of the working site, the molten metal temperature, and mold rotation speed were selected as process parameters to be collected. The sensors were selected in consideration of the detailed product specifications and cost required for each process parameter, and the circuit was configured using a NodeMCU board capable of wireless communication for IoT-based devices. After designing the circuit, PCB boards were prepared for each parameter, and each device was installed on site considering the working environment. After the on-site installation process, it was confirmed that the level of satisfaction with the safety of the workers and the efficiency of process management increased. Also, it is expected that it will be possible to link process data and quality data in the future, if process parameters are continuously collected. The IoT-based device designed in this study has adequate reliability at a low cast, meaning that the application of this technique can be considered as a cornerstone of data collecting at foundries.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.301-308
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• 2022

Algae is an indispensable primary producer in the ecosystem by supplying energy to consumers in the aquatic ecosystem, and is largely divided into green algae, blue-green algae, and diatoms. In the case of blue-green algae, the water temperature rises, which occurs in the summer and overgrows, which is the main cause of the algae bloom. Recently, the change in the occurrence time and frequency of the algae bloom is increasing due to climate change. Existing algae survey methods are performed by collecting water and measuring through sensors, and time, cost and manpower are limited. In order to overcome the limitations of these existing monitoring methods, research has been conducted to perform remote monitoring using spectroscopic devices such as multispectral and hyperspectral using satellite image, UAV, etc. In this study, we tried to confirm the possibility of species classification of remote monitoring through laboratory-scale experiments through algal culture and river water collection. In order to acquire hyperspectral images, a hyperspectral sensor capable of analyzing at 400-1000 nm was used. In order to extract the spectral characteristics of the collected river water for classification of algae species, filtration was performed using a GF/C filter to prepare a sample and images were collected. Radiation correction and base removal of the collected images were performed, and spectral information for each sample was extracted and analyzed through the process of extracting spectral information of algae to identify and compare and analyze the spectral characteristics of algae, and remote sensing based on hyperspectral images in rivers and lakes. We tried to review the applicability of monitoring.

• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.59-69
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• 2007

The aim of this study was to investigate teachers' perceptions on MBL (microcomputer-based laboratory) experiment training program for teachers, the expecting effects of MBL experiment and application of MBL experiment after conducting MBL experiment training for science classes in schools. This study showed that most of the teachers who participated in the training program thought that the MBL experiment training program was very useful and instructive. Many teachers considered that MBL experiments using a computer could decrease time spent in the experiment by accurate and fast data collection and analysis. They also thought that the reduced time could be used more effectively in the analysis of experimental data and discussion activities leading to correct concept formation as well as in the development of graphical analysis and science process skills. However, they thought that MBL experiments were ineffective in learning how to operate experiment apparatus. This study also revealed that most teachers intended to apply MBL experiments in real classrooms context right after the training course and they pointed out many obstacles in introducing MBL experiments into their classrooms such as a budget to purchase equipment, poor laboratory conditions, and few MBL experiment training opportunities. In order to apply MBL experiment into the real classrooms, further changes were suggested as follows; development of technologies to reduce unit cost of equipment for MBL experiments, production and supply of many kinds of sensors, development of MBL experiment materials, and expansion of the training program for teachers.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.127-145
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• 2023

As the importance of strengthening port security is increasing, it is necessary to conduct a perceptual study on port facility users who pay for port security services first. This study aims to identify improvements in the port security function of Busan Port and contribute to the future development of port security in Korea. A total of 125 questionnaires were collected from port facility security fee collectors at Busan Port. Based on the collected data, exploratory factor analysis, traditional IPA, and modified IPA were conducted. In conclusion, first, the physical function of port security is the most important and should be continuously maintained and strengthened. Second, improving the professionalism of port security personnel is most urgent, and the port security education system needs to be improved. Finally, it is necessary to gradually develop the port security information service function in consideration of future development possibilities.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.261-271
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• 2016

Citrus is an economically important fruit crop widely growing worldwide. However, citrus production largely depends on natural hybrid selection and bud sport mutation. Unique botanical features including long juvenility, polyembryony, and QTL that controls major agronomic traits can hinder the development of superior variety by conventional breeding. Diverse factors including drastic changes of citrus production environment due to global warming and changes in market trends require systematic molecular breeding program for early selection of elite candidates with target traits, sustainable production of high quality fruits, cultivar diversification, and cost-effective breeding. Since the construction of the first genetic linkage map using isozymes, citrus scientists have constructed linkage maps using various DNA-based markers and developed molecular markers related to biotic and abiotic stresses, polyembryony, fruit coloration, seedlessness, male sterility, acidless, morphology, fruit quality, seed number, yield, early fruit setting traits, and QTL mapping on genetic maps. Genes closely related to CTV resistance and flesh color have been cloned. SSR markers for identifying zygotic and nucellar individuals will contribute to cost-effective breeding. The two high quality citrus reference genomes recently released are being efficiently used for genomics-based molecular breeding such as construction of reference linkage/physical maps and comparative genome mapping. In the near future, the development of DNA molecular markers tightly linked to various agronomic traits and the cloning of useful and/or variant genes will be accelerated through comparative genome analysis using citrus core collection and genome-wide approaches such as genotyping-by-sequencing and genome wide association study.

• The Korean Journal of Archival Studies
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• no.1
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• pp.23-76
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• 2000

In this paper, I examined what have been researched and determined about preservation strategy and selection of preservation media in the western archival community. Archivists have primarily been concerned with 'preservation' and 'use' of archival materials worth of being preserved permanently. In the new information era, preservation and use of archival materials were faced with new challenge. Life expectancy of paper records was shortened due to acidification and brittleness of the modem papers. Also emergence of information technology affects the traditional way of preservation and use of archival materials. User expectations are becoming so high technology-oriented and so complicated as to make archivists act like information managers using computer technology rather than traditional archival handicraft. Preservation strategy plays an important role in archival management as well as information management. For a cost-effective management of archives and archival institutions, preservation strategy is a must. The preservation strategy encompasses all aspects of archival preservation process and practices, from selection of archives, appraisal, inventorying, arrangement, description, conservation, microfilming or digitization, archival buildings, and access service. Those archival functions should be considered in their relations to each other to ensure proper preservation of archival materials. In the integrated preservation strategy, 'preservation' and 'use' should be combined and fulfilled without sacrificing the other. Preservation strategy planning is essential to determine the policies of archives to preserve their holdings safe and provide people with a maximum access in most effective ways. Preservation microfilming is to ensure permanent preservation of information held in important archival materials. To do this, a detailed standardization has been developed to guarantee the permanence of microfilm as well as its product quality. Silver gelatin film can last up to 500 years in the optimum storage environment and the most viable option for permanent preservation media. ISO and ANIS developed such standards for the quality of microfilms and microfilming technology. Preservation microfilming guidelines was also developed to ensure effective archival management and picture quality of microfilms. It is essential to assess the need of preservation microfilming. Limit in resources always put a restraint on preservation management. Appraisal (and selection) of what to be preserved was the most important part of preservation microfilming. In addition, microfilms with standard quality can be scanned to produce quality digital images for instant use through internet. As information technology develops, archivists began to utilize information technology to make preservation easier and more economical, and to promote use of archival materials through computer communication network. Digitization was introduced to provide easy and universal access to unique archives, and its large capacity of preserving archival data seems very promising. However, digitization, i.e., transferring images of records to electronic codes, still, needs to be standardized. Digitized data are electronic records, and st present electronic records are very unstable and not to be preserved permanently. Digital media including optical disks materials have not been proved as reliable media for permanent preservation. Due to their chemical coating and physical character using light, they are not stable and can be preserved at best 100 years in the optimum storage environment. Most CD-R can last only 20 years. Furthermore, obsolescence of hardware and software makes hard to reproduce digital images made from earlier versions. Even if when reformatting is possible, the cost of refreshing or upgrading of digital images is very expensive and the very process has to be done at least every five to ten years. No standard for this obsolescence of hardware and software has come into being yet. In short, digital permanence is not a fact, but remains to be uncertain possibility. Archivists must consider in their preservation planning both risk of introducing new technology and promising possibility of new technology at the same time. In planning digitization of historical materials, archivists should incorporate planning for maintaining digitized images and reformatting them in the coming generations of new applications. Without the comprehensive planning, future use of the expensive digital images will become unavailable. And that is a loss of information, and a final failure of both 'preservation' and 'use' of archival materials. As peter Adelstein said, it is wise to be conservative when considerations of conservations are involved.