• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.224-230
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• 2010

The purpose of this study was to develop position control system of an electric actuator for automatic shuttle shifting of a tractor. The electric actuator was installed at the link of the forward-reverse gearshift of the tractor transmission, and controlled in the ranges of forward, neutral, and reverse positions. The position control system of the electric actuator was developed based on PID (Proportional Integral Derivative) controller and transfer function of the electric actuator. The coefficients of the PID controller were determined by Ziegler-Nichols (Z-N) method and optimized using simulation program. The prototype AMT (Automated Manual Transmission) test unit of the tractor was installed and used to evaluate the performance of the position control. The evaluation system for the control performance consisted of forward-reverse actuator, motor driver, and controller. The tests were conducted as the controlled positions of the actuator were changed from neutral position to forward, neutral, and reverse positions in sequence. The sequential tests were repeated 20 times. The operations of changing the gearshift were considered as the step response of the control system. Maximum overshoot, settling time, and steady-state error were analyzed. The results showed that performance of the position control system was reasonable and qualified. The maximum overshoots, the steady-state errors, and the settling times of the position control system were 10~20%, 1~5%, and 0.92~1.49 sec, respectively. The modifications of the electric actuator will be required to enhance the performance of position control during field operation.

• Journal for History of Mathematics
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• v.33 no.2
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• pp.75-101
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• 2020

We considered the context of the publications and transmissions of mathematics books using the Korean traditional book lists and the catalogues of woodblocks in the Joseon Dynasty and DaeHan大韓 Empire period. Among the results, this paper first describes the context of the publication and transmission of mathematics textbooks of national math exams算學取才 in the first half of Joseon, adding a step more specific to the facts known so far. In 1430, 『YangHui SanFa楊輝算法』, 『XiangMing SuanFa詳明算法』, 『SuanXue QiMeng算學啓蒙』, 『DiSuan地算』, 『WuCao SuanJing五曹算經』 were selected as the textbooks of national math exams算學取才. 『YangHui SanFa』, 『XiangMing SuanFa』, 『DiSuan』 were included in the catalogues of woodblocks in the Joseon Dynasty before the Japanese invasion in 1592, and we could see that Gyeongju慶州, Chuncheon春川, and Wonju原州 were the printing centers of these books. Through other lists, literature records and real text books, it came out into the open that 『XiangMing SuanFa』 was published as movable print books three times at least, 『SuanXue QiMeng』 four times at least in the first half of Joseon Dynasty. And 『XiangMing SuanFa』 was published at about 100 years later than 『YangHui SanFa楊輝算法』 as xylographic books, 『SuanXue QiMeng』 was published twice as xylographic books in the second half of Joseon Dynasty. Whether or not the list of royal books included the Korean or Chinese versions of these books, and additional notation in that shows how the royal estimation of these books changed.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.465-474
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• 2009

The emergence of the digital age has changed the paradigm of education. Recently, the new paradigm needs new digital books that contain more interactive contents. Our goal is to design the digital textbook with convenient interfaces and cutting effects for interactive and effective education. To achieve these goals, we propose interfaces and contents which are designed after a lot of discussion with educational experts. In the implementation step, cutting algorithm is proposed to generate the cut planes of the 3D objects, based on the free strokes specified by the users. In order to test the performance of the contents, the testbed was implemented so that students try our digital book and present their evaluation results on the convenience and the effectiveness.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.847-854
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• 2012

The demand for noise barriers and necessity for the installation are highly growing because residential areas have become diverse and locational priority is changed to consider how to approach highway easily. However, public annoyance to the noise generated from highway is continued despite lots of noise barrier are installed. Moreover, there are growing concerns to maintain noise barriers to be free from losing transparency, dust stack, and shock fracture. To resolve these issues, it is suggested to develop new polymer materials and conceptually new noise barrier. In this study, as a first step to develop a new noise barrier to overcome current technological challenges as well as economic issues, recent research trends have been analyzed and found the direction for the future research in terms of material, supplementary function, and patterning.

• Perspectives in Nursing Science
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• v.3 no.1
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• pp.47-60
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• 2006

BACKGROUND: Social, legal, and economic factors have changed the delivery of care to elderly who are frail and/or chronically ill. Increasing number of the elderly are now treated in the community, while living with or in close proximity to their family. It is evident that families play a major role of support for elderly persons in our society. This paper provides a review and analysis of studies that have investigated informal caregiving issues encompassing physical, psychological, emotional, and social domains. RESULTS OF THE REVIEW: Family caregiving often interfered with workplace and other responsibilities, creating physical, emotional, and financial stress for caregivers. Relatively high volumes of research addressed caregiving issues in the families of Alzheimer patients and in the areas of emotional and psychological impact of caregiving. Few studies explicitly investigated the role of informal caregivers in the management of other chronic conditions such as stroke or depression or physical consequences of long-term caregiving. While most studies were focused on negative aspects of caregiving, a few studies found it rewarding. Often the burden, stress, and socio-economic effects on the family caregiving for an elderly person were not sufficiently appreciated. CONCLUSIONS: Positive outcomes for both the caregiver and the care recipient are more likely to occur when effective levels of collaboration exist between health professionals and caregivers. As a first step, a better understanding of the caregiving experience such as caregiver characteristics, care recipient characteristics, and social stigma is important for nurses to minimize the burden of care so that appropriate interventions can be developed. In addition, further studies are needed to examine the role and needs of informal caregivers in the care of increasing number of frail and/or chronic ill elderly treated in the community.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.649-652
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• 2005

The camera cellular phone has a large portion of cellular phone market in recent year. The variety of a customer demand makes a fast model change and the spatial resolution is changed from VGA to multi-mega pixel. The 1.3 mega pixel (MP) camera cellular phone was first released into the Korean market in October 2003. The major cellular phone companies released a 2MP camera cellular phone that supports zoom function and a 2MP camera cellular phone is settled down with the Korea cellular phone market. It makes a keen competition in price and demands automation for phone camera module. There is an increasing requirement for the automatic assembly to correspond to a fast model change. The hard automation techniques that rely on dedicated manufacturing system are too inflexible to meet this requirement. Therefore in this study, this system is designed with the flexibility concept in order to cope with phone camera module change. The system has a same platform that has X-Y-Z motion or X-Z motion with ${\mu}m$order accuracy. It has a special gripper according to the type of a component to be put together. If the camera model changes, the gripper may be updated to fit for the camera module. The controller of this system acquires the data sets that have the information about the assembly part by the tray. This information is obtained ahead of an inspection step. The controller excludes an inferior part to be assembled by using this information to diminish the inferior goods. The assembly jig used in this system has a function of self adjustment that reduces the tact time and also diminish the inferior goods. Finally, the intelligent assembly system for phone camera module will be designed to get a flexibility to meet model change and a high productivity with a high reliability.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8247-8252
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• 2016

Background: The ubiquitin-proteasome system (UPS) degrades a variety of proteins which attach to specific signals. The ubiquitination pathway facilitates degradation of damaged proteins and regulates growth and stress responses. This pathway is altered in various cancers, including acute lymphoblastic leukemia, head and neck squamous cell carcinoma and breast cancer. Recently it has been reported that expression of newly characterized human genes, UBE2Q1 and UBE2Q2, putative members of ubiquitin-conjugating enzyme family (E2), has been also changed in colorectal cancer. Epigenetics is one of the fastest-growing areas of science and nowadays has become a central issue in biological studies of diseases. According to the lack of information about the role of epigenetic changes on gene expression profiling of UBE2Q1 and UBE2Q2, and the presence of CpG islands in the promoter of these two human genes, we decided to evaluate the promoter methylation status of these genes as a first step. Materials and Methods: The promoter methylation status of UBE2Q1 and UBE2Q2 was studied by methylation-specific PCR (MSP) in tumor samples of 60 colorectal cancer patients compared to adjacent normal tissues and 20 non-malignant controls. The frequency of the methylation for each gene was analyzed by chi-square method. Results: MSP results revealed that UBE2Q2 gene promoter were more unmethylated, while a higher level of methylated allele was observed for UBE2Q1 in tumor tissues compared to the adjacent normal tissues and the non malignant controls. Conclusions: UBE2Q1 and UBE2Q2 genes show different methylation profiles in CRC cases.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.695-702
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• 1994

Current study was undertaken to explain the structural evolution and corresponding changes in the properties of calcium aluminate glasses with the variation of SiO2 doping concentration. Calcium aluminate glasses in the compositional ranges of (100-x)(0.6CaO+0.4Al2O3)+xSiO2(where x=0~60) were fabricated. DTA analysis confirmed an anomalous behavior in glass transition temperature (Tg) with the maximum of 887$^{\circ}C$ and minimum of 859$^{\circ}C$ when x=5 and 50, respectively. densities and refractive indices monotonically decreased with increasing SiO2 content and IR transmitting cutoff shifted to shorter wavelength side when the amount of added SiO2 exceeded 5 mole%. IR fundamental vibration absorption peaks showed the change that NBOs were inclined to SiO4 tetrahedron in the low-silica region and NBO per SiO4 tetrahedra changed from 2 to 0 with increasing silica content. Based on the analysis of IR fundamental vibration absorption peaks, the model of the structural change can be proposed in three step: 1) SiO4 scavenged the NBOs located at AlO4-tetrahedra, which resulted in the increased of Tg values, 2) NBOs located in the main network again with a decrease in Tg, and 3) dominated by the decrease in the relative amount of NBOs in the glass system, where Tg re-increased.

• Journal of the Korean GEO-environmental Society
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• v.15 no.10
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• pp.29-34
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• 2014

In order to examine strength properties depended on climate changes of solidified soil amended by porosity silica which enhance harms of cement, this study conducts a wetting and drying repetition test and then, attempts to verify strength properties before and after solidified soil gets environmental influence. Test pieces for the unconfined compression test changed the mixing ratio of solidified soil compared to mixed soil weigh to 5 %, 10 % and 15 %. For each step, it was created by mixing 0.5 %, 1.0 % and 1.5 % of wood chips, and curing period for 7, 14, and 28 days. Then, the wetting and drying repetition process was repeated 0, 3, 6, and 12 cycles to analyze mechanical properties. To also evaluate changes of relative dynamic elastic modulus before and after the wetting and drying, dynamic elastic modulus tests were conducted when each cycle was completed.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.258-261
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• 2009

In this work, we the ettect on extraction amounts and general composition content of phytoestrogen genistein and formononetin extracted from Sophoraflavescens Aiton by various ultrasonic waves(35, 72, and 170 KHz) and extraction time(30, and 60 min) were compared using extraction solvent water 100%. The pretreatment step was composed of ultrasonic waves extraction, filtration, concentration, and membrane filtration. The extracted sample was analyzed by reversed-phase high performance liquid chromatography(RP-HPLC). And the mobile phase applied was linearly changed with A/B of 80/20~65/35 vol% for 60 min(A water/acetic acid, 99.9/0.1 vol%, B acetonitrile/acetic acid, 99.9/0.1 vol%). The experimental results, general composition carbohydrate(0.255 to 0.413%) excepts, other ingredients was confirmed almost similarly. Also, The highest yield of extraction amount 3.17g was obtained by ultrasonic waves with a frequency of 170 KHz and an extraction time of 60 min. This work offers would be useful for chemical and biological studies of natural plants and its products.