• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.126-132
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• 2005

UV disinfection system allows the disinfection of municipal and industrial water and wastewater without the use of expensive chlorination and dechlorination techniques, labor intensive equipments In traditional ultraviolet systems the UV lamps are seperated from water by quartz sleeves. quartz is one of. the few materials that is virtually transparent to UV light, the UV lamp is placed inside the Quartz sleeve. UV light from the lamp is passed through the quartz and into the water, thereby providing disinfection. In fluoropolymer tube-used non-contact UV systems, the water flows through fluoropolymer plastic tubes. banks of UV lamps surround these tubes such that each tube gets exposed to ultra violet light from all sides. in non-contact design the lamps operates at almost constant temperature. this design is extremly efficient in the utilization of UV energy and superior to conventional contact- systems.

• Journal of Periodontal and Implant Science
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• 제40권3호
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• pp.111-118
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• 2010

Purpose: The aim of this study was to investigate whether vitrification in the cryopreservation of periodontal ligament (PDL) cells could be useful for tooth banking. Methods: In step 1, primary cultured human PDL cells were cryopreserved in 100% conventional cryopreservation media and 100% vitrification media (ESF40 media) in different temperatures for 2 weeks. In step 2, a series of modified vitrification formulae named T1 (75% vitrification media + 25% F-media), T2 (50% vitrification media + 50% F-media) and T3 (25% vitrification media + 75% F-media) were used to store PDL cells for 2 weeks and 4 weeks in liquid nitrogen. MTT assay was performed to examine the viability of PDL cells. Results: Maximum cell viability was achieved in cells stored in 100% conventional cryopreservation media at $-196^{\circ}C$ (positive control group) in step 1. Compared to the positive control group, viability of the cells stored in 100% vitrification media was very low as 10% in all test conditions. In step 2, as the percentage of vitrification media decreased, the cell viability increased in cells stored for 2 weeks. In 4-week storage of cells in step 2, higher cell viability was observed in the T2 group than the other vitrification formulae while the positive control group had the highest viability. There was no statistically significant difference in the cell viability of 2-week and 4-week stored cells in the T2 group. Conclusions: These observations indicate 100% vitrification media is not successful in PDL cell cryopreservation. Conventional cryopreservation media is currently the most appropriate media type for this purpose while T2 media would be interesting to test for long-term storage of PDL cells.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권3호
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• pp.133-139
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• 2002

In this paper, a prototype of an active auxiliary quasi-resonant DC link (QRDCL) snubber assisted voltage source bidirectional power converter (AC to DC and DC to AC) operating at zero voltage soft-switching (BVS) PWM nlode is presented for a Battery Energy Storage System (BESS). The operating principle of this QRDCL circuit and multifunctional control-based converter system, including PWM inverter mode in which energy flows from the battery bank to the three-phase utility-grid in addition to an active PWM converter mode in which energy flows from the utility-grid to the battery banks are described respectively by the control implementation on the basis of d-q coordinate plane transformation. The multifunctional operation characteristics of this three-phase ZVS PWM bi-directional converter with QRDCL is demonstrated fer a BESS under the power conditioning and processing schemes of energy supply mode and energy storage mode, and compared with a conventional three-phase hard switching PWM bi-directional converter for a BESS. The effectiveness of the three-phase ZVS PWM hi-directional converter with QRDCL is proven via the simulation analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3182-3202
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• 2015

Flexibly expanding the storage capacity required to process a large amount of rapidly increasing unstructured log data is difficult in a conventional computing environment. In addition, implementing a log processing system providing features that categorize and analyze unstructured log data is extremely difficult. To overcome such limitations, we propose and design a MongoDB-based unstructured log processing system (MdbULPS) for collecting, categorizing, and analyzing log data generated from banks. The proposed system includes a Hadoop-based analysis module for reliable parallel-distributed processing of massive log data. Furthermore, because the Hadoop distributed file system (HDFS) stores data by generating replicas of collected log data in block units, the proposed system offers automatic system recovery against system failures and data loss. Finally, by establishing a distributed database using the NoSQL-based MongoDB, the proposed system provides methods of effectively processing unstructured log data. To evaluate the proposed system, we conducted three different performance tests on a local test bed including twelve nodes: comparing our system with a MySQL-based approach, comparing it with an Hbase-based approach, and changing the chunk size option. From the experiments, we found that our system showed better performance in processing unstructured log data.

• Journal of Preventive Medicine and Public Health
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• 제40권2호
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• pp.95-101
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• 2007

Focusing on complex diseases of public health significance, strategic issues regarding the on-going Korean Genome Cohort were reviewed: target size and diseases, measurements, study design issues, and follow-up strategy of the cohort. Considering the epidemiologic characteristics of Korean population as well as strengths and drawbacks of current research environment, we tried to tailor the experience of other existing cohorts into proposals for this Korean study. Currently 100,000 individuals have been participating the new Genome Cohort in Korea. Target size of de novo collection is recommended to be set as between 300,000 to 500,000. This target size would allow acceptable power to detect genetic and environmental factors of moderate effect size and possible interactions between them. Family units and/or special subgroups are recommended to parallel main body of adult individuals to increase the overall efficiency of the study. Given that response rate to the conventional re-contact method may not be satisfactory, successful follow-up is the main key to the achievement of the Korean Genome Cohort. Access to the central database such as National Health Insurance data can provide enormous potential for near-complete case detection. Efforts to build consensus amongst scientists from broad fields and stakeholders are crucial to unleash the centralized database as well as to refine the commitment of this national project.

• 한국전문물리치료학회지
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• 제19권3호
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• pp.124-131
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• 2012

Most conventional instruments measuring disability rely on total score by simply adding individual item responses, which is dependent on the items chosen to represent the underlying construct (test-dependent) and a test statistic, such as coefficient alpha for the estimate of reliability, varying from sample to sample (sample-dependent). By contrast, item response theory (IRT) method focuses on the psychometric properties of the test items instead of the instrument as a whole. By estimating probability that a respondent will select a particular rating for an item, item difficulty and person ability (or disability) can be placed on same linear continuum. These estimates are invariant regardless of the item used (test-free measurement) and the ability of sample applied (sample-free measurement). These advantages of IRT allow the creation of invariantly calibrated large item banks that precisely discriminate the disability levels of individuals. Computer adaptive testing (CAT) method often requiring a testing algorithm promise a means for administering items in a way that is both efficient and precise. This method permits selectively administering items that are closely matched to the ability level of individuals (measurement precision) and measuring the ability without the loss of precision provided by the full item bank (measurement efficiency). These measurement properties can reasonably be achieved using IRT and CAT method. This article aims to investigate comprehensive overview of the existing disability instrument for back pain and to inform physical therapists of an alternative innovative way overcoming the shortcomings of conventional disability instruments. An understanding of IRT and CAT method will equip physical therapist with skills in interpreting the measurement properties of disability instruments developed using the methods.

• 한국측량학회지
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• 제18권1호
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• pp.51-57
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• 2000

레이저 프로파일링 시스템의 등장으로, 기존에는 얻을 수 없었던 도시 지역에 대한 DTM이 취득 가능해졌고, 더욱 정확한 정사투영영상 또한 제작할 수 있게 되었다. 하지만, 높이변화를 보이는 자연지물과 인공구조물이 있는 지역에 대해 기존의 정사투영사진 제작기법이 적용될 때, 폐색이나 이중매핑과 같은 문제가 발생하여 정사투영영상의 품질을 저해하는 주요한 원인이 된다. 따라서, 본 연구에서는 카메라의 외부표정요소와 DTM을 이용하여 폐색영역을 탐지하고, 폐색이 안된 다른 영상의 정보를 통해 폐색영역을 복원하여 더욱 완전한 정사투영영상을 제작할 수 있는 알고리즘을 제안하였다. 제안된 알고리즘에 의해 자연지물이나 인공구조물에 의한 폐색영역을 탐지할 수 있었고 폐색영역의 많은 부분을 부가영상을 이용하여 복원하였다. 건물에 대한 사전지식을 이용하여 폐색영역을 탐지하는 국내 연구가 있지만, 본 연구는 건물에 대한 부가정보나 모델링을 사용하지 않고 DTM과 카메라 외부표정요소만을 이용하여 폐색영역을 탐지한다는 점에서 이러한 연구들과 차별성을 가진다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권2호
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• pp.742-756
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• 2022

A flood of information has occurred with the rise of the internet and digital devices in the fourth industrial revolution era. Every millisecond, massive amounts of structured and unstructured data are generated; smartphones, wearable devices, sensors, and self-driving cars are just a few examples of devices that currently generate massive amounts of data in our daily. Machine learning has been considered an approach to support and recognize patterns in data in many areas to provide a convenient way to other sectors, including the healthcare sector, government sector, banks, military sector, and more. However, the conventional machine learning model requires the data owner to upload their information to train the model in one central location to perform the model training. This classical model has caused data owners to worry about the risks of transferring private information because traditional machine learning is required to push their data to the cloud to process the model training. Furthermore, the training of machine learning and deep learning models requires massive computing resources. Thus, many researchers have jumped to a new model known as "Federated Learning". Federated learning is emerging to train Artificial Intelligence models over distributed clients, and it provides secure privacy information to the data owner. Hence, this paper implements Federated Averaging with a Deep Neural Network to classify the handwriting image and protect the sensitive data. Moreover, we compare the centralized machine learning model with federated averaging. The result shows the centralized machine learning model outperforms federated learning in terms of accuracy, but this classical model produces another risk, like privacy concern, due to the data being stored in the data center. The MNIST dataset was used in this experiment.

• 동아시아경상학회지
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• 제2권4호
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• pp.56-64
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• 2014

Today, travelers are provided large amount information which includes Web sites and tourist magazines about introduction of tourist spot. Many approaches have been proposed to analyze the large amount of available information with the aim of discovering the most popular Points of Tourist Interest and routes. However, it is not easy for users to process the information in a short time. Therefore travelers prefer to receive pertinent information easier and have that information presented in a clear and concise manner. Whether you are looking for banks by company, foreign exchange services, free wireless hotspots, touristic attractions, campsites, supermarkets, restaurants, cinemas, The aim of POI Tourism Services is to enable tourists to find spots that only the locals know, giving the tourists opportunity to the tourists to explore new areas of the place like never before. This paper proposes find the scope for a personalized service for tourist "Special Interest Tourism" recommendation for tourists who travel within India & for the benefit of Foreign Nationals who visit the country. The major focus of the study is to understand the demand for such a service being integrated into the conventional tour package. The major findings made during the course of the show that the market for "Special Interest Tourism" based services stands at approximately 63%. Travel today is mainly for the people from the middle income group having a fixed budget while traveling and would like economic travel solutions that fit their budget. This accounts for a major part of the market for the service. Most tourist prefer to go on week end getaways or trips that last more than a week, this means that a specialized trip plan based on the travelers interests is feasible with these type of travelers. Maximum demand for "Special Interest Tourism" based services would be during the festive seasons.

• 전기전자학회논문지
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• 제15권1호
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• pp.29-36
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• 2011

기존에 ADPLL(All Digital Phase Locked Loop)에서는 DCO(Digitally Controlled Oscillator)의 해상도를 향상시키기 위해 주로 dithering 기법이 사용되었다. 본 논문에서는 dithering 방식에서 발생하는 문제점을 보안하고자 DAC를 이용한 DCO의 해상도 확보 방법을 제안하였다. $0.13{\mu}m$ CMOS 공정을 이용하여 고해상도의 2.4GHz LC DCO를 무선 로컬 네트워크 통신에 적용 가능하도록 설계하였다. 설계된 DCO는 900MHz의 주파수 튜닝 범위를 가지고 발진하며 58.8Hz의 해상도를 보여준다. 주파수 컨트롤은 coarse, fine, DAC 배랙터 bank에 의해서 이루어지며, coarse와 fine bank는 PMOS 배랙터로, DAC bank는 NMOS 배랙터로 구성되었다. 각 배랙터 bank는 8비트의 디지털 입력으로 컨트롤된다. 설계된 DCO의 위상잡음은 1MHz 옵셋에서 -123.8dBc/Hz이다. 설계된 DCO는 공급전압 1.2V에서 4.2mA의 전류를 소모한다.