• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.263-266
• /
• 1996

A method to determine an optimal temperature trajectory that guarantees polymer products having controlled molecular weight distribution and desired values of molecular weight is presented. The coordinate transformation method and the optimal control theory are applied to a batch PMMA polymerization system to calculate the optimal temperature trajectory. Coordinate transformation method converts the original fixed-end-point, free-end-time problem to a free-end-point, fixed-end-time problem. The idea is that by making the reactor temperature track the optimal temperature trajectory one may be able to produce polymer products having the prespecified physical property in a minimum time. The on-line control experiments with the PID control algorithm have been conducted to establish the validity of the scheme proposed in this study. The experimental results show that prespecified polymer product could be obtained with tracking the calculated optimal temperature trajectory.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.350-355
• /
• 2005

This paper presents a new approach for hysteresis modeling of a magnetorheological (MR) fluid. The field-dependent hysteresis of MR fluid is investigated using the Preisach model. The commercial MR Product (MRF-132LD, Lord Corporation) is employed. Its field-dependent shear stress is then obtained using a rheometer (MCR 300, Physica). In order to show the applicability of the Preisach model to the MR fluid, two significant Properties; the minor loop property and the wiping-out property are experimentally examined. Subsequently, the Preisach model for the MR fluid is identified using experimental first order descending (FOD) curves in discrete manner. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.1 s.106
• /
• pp.3-11
• /
• 2006

This paper presents a new approach for hysteresis modeling of a magnetorheological (MR) fluid. The field-dependent hysteresis of MR fluid is investigated using the Preisach model. The commercial MR product (MRF-132LD, Lord Corporation) is employed. Its field-dependent shear stress is then obtained using a rheometer (MCR 300, Physica). In order to show the applicability of the Preisach model to the MR fluid, two significant properties; the minor loop property and the wiping-out. property are experimentally examined. Subsequently, the Preisach model for the MR fluid is identified using experimental first order descending (FOD) curves in discrete manner. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Journal of Powder Materials
• /
• v.20 no.2
• /
• pp.85-99
• /
• 2013

Powder metallurgy applied rapid heating to sintering starting year 1900. Since 1970 the study has intensified. Now rapid sintering concepts embrace a spectrum of options ranging from dunk cycles to microwave, induction, exothermic, electric field, and spark approaches. Most of the efforts are targeting reduced microstructure coarsening during sintering, although reduced material decomposition is another common goal. The efforts are impressive for simple shapes and success metrics such a small grain size after densification. Several barriers need to be removed prior to application in powder metallurgy commercial sintering. Rapid heating research needs to focus on significant property gains, accurate product dimensions, and lower costs. So far each property gain obtained with rapid heating is matched by traditional sintering and composition changes. Several examples are cited to show the goals for the next round of innovations.

• Corrosion Science and Technology
• /
• v.2 no.2
• /
• pp.102-108
• /
• 2003

The surface treatments. Chrome/Manganese and Modified Chrome Pickle, that are treated to improve the anti-corrosion property which is needed to increased the probability of prototype product enabled the sand cast Magnesium test specimens to have better corrosion resistance than non-treated one. Sand cast Magnesium specimens which was treated only with chemical conversion coating had same corrosion resistance with the Steel specimens plated by Zinc, and the another one that had the finishing treatment(painting) worked on the chemical surface treatment had the corrosion resistance property to meet to FPO-3 requirement. We also investigated the multiple finishing system(chemical surface treatment + 3 coating) to test the severe condition that magnesium should to endure.

• Journal of Oriental Neuropsychiatry
• /
• v.34 no.3
• /
• pp.247-257
• /
• 2023

Objectives: To analyze the trend of Korean patents of natural product extracts for depression. This study also aimed to enhance the development and application of natural product extracts for depression in Korean herbal medicine. Methods: We searched the Korea Intellectual Property Rights Information Service and Science ON to collect Korean patent data of natural product extracts for depression. Two authors independently screened and assessed full texts of screened patents for eligibility. Included patents were analyzed both quantitatively and qualitatively. Results: A total of 62 patents from 2002 to December 2021 were included for analysis. The number of patents has constantly increased since 2002. Glycyrrhiza uralensis Fischer, Perilla frutescens Britton var. acuta Kudo, Zizyphus jujuba Miller var. inermis Rehder were frequently used among 62 patents. Alcohol extraction was mostly used, followed by water extraction and ethyl extraction regarding extract methods. Eight patents were herbal medicine used for treating depression in Korean Medicine. Conclusions: Various Korean herbal medicine and minerals were used as natural-products for treating depression. These results provide fundamental data that can be used for inventing new patents using Korean herbal medicine, developing new natural product extracts for depression, and extending the range of application of these products in clinical setting.

• Knowledge Management Research
• /
• v.21 no.1
• /
• pp.197-210
• /
• 2020

The smart speaker includes an AI assistant function in the existing portable speaker, which enables a person to give various commands using a voice and provides various offline services associated with control of a connected device. The speed of domestic distribution is also increasing, and the functions and linked services available through smart speakers are expanding to shopping and food orders. Through text mining-based customer review analysis, there have been many proposals for identifying the impact on customer attitudes, sentiment analysis, and product evaluation of product functions and attributes. Emotional investigation has been performed by extracting words corresponding to characteristics or features from product reviews and analyzing the impact on assessment. After obtaining the topic from the review, the effect on the evaluation was analyzed. And the market competition of similar products was visualized. Also, a study was conducted to analyze the reviews of smart speaker users through text mining and to identify the main attributes, emotional sensitivity analysis, and the effects of artificial intelligence attributes on product satisfaction. The purpose of this study is to collect blog posts about the user's experiences of smart speakers released in Korea and to analyze the attitudes of customers according to their attributes. Through this, customers' attitudes can be identified and visualized by each smart speaker product, and the positioning map of the product was derived based on customer recognition of smart speaker products by collecting the information identified by each property.

• Korean Journal of Agricultural Science
• /
• v.42 no.2
• /
• pp.131-139
• /
• 2015

This study investigated the quality properties of smoked breast meats produced by fresh and frozen-thawed duck meat. Each thirty breast meats from fresh and frozen-thawed duck carcass was used for this study. The yield of smoked breast meat was measured right after curing and smoking of raw duck breast meat. And, the number of total aerobic bacteria, color, texture, and sensory property of vacuum-packaged smoked breast meats were evaluated during storage at $4^{\circ}C$ for 28 days. No significant difference was found in yield between smoked breast meats produced by fresh and thawed duck meats (p>0.05). The number of total aerobic bacteria and color of smoked breast meat produced by thawed duck meat were not significantly different compared with those by fresh one throughout storage period (p>0.05). The all texture properties were not significantly different between smoked breast meats produced by fresh and thawed duck meats by 14 days of storage (p>0.05). However, on day 21 and 28, the hardness and gumminess of smoked breast meat produced by fresh duck meat were significantly higher than those by thawed one (p<0.05). In sensorial property, smoked breast meat produced by thawed duck meat received significantly high scores in color, juiciness, and tenderness on days 0, 14, and 28 and in flavor and overall acceptance on days 0 and 14 compared with those by fresh one (p<0.05). Therefore, we concluded that the use of thawed duck meat for producing smoked duck meat product may be not worse than the use of fresh duck meat in quality of smoked duck meat product. In addition, the use of thawed duck meat may be better in sensorial quality of smoked duck meat product than that of fresh one.

• Journal of Korea Multimedia Society
• /
• v.9 no.8
• /
• pp.939-949
• /
• 2006

With the development of industry, product data management system is becoming more and more important. An expanded view of product definition function that include a bill of material and routing database, current and historical engineering data and specifications and engineering changes order history. PDM (Product Data Management) systems hold and manage such material as product specifications, plans, geometric models, CAD drawings and images. Furthermore, PDM enables companies producing complex products to spread product data in to the entire launch process. Especially, PDTnet XML Schema is an international standard for exchanging of PDM data. But PDTnet XML Schema differs from existing XML Schema in the way that its property of IDREF/IDREFS is irregular. Therefore it is important factor that. what do we use storage devices and storage techniques. We developed storage techniques and application supporting various query types and preserving PDTnet XML Schema using a relational database that guaranteeing the performance nowadays. In this paper, we will show that our storage techniques minimize repeated data and optimize query processing by using application comparison with storage techniques of existing XML Schema data.

• Korean Journal of Heritage: History & Science
• /
• v.47 no.3
• /
• pp.172-187
• /
• 2014

The purpose of this paper is to examine how the 'tradition' has been identified and used concretely on the protection system of cultural property. Firstly, this paper investigated the historical process and aspects that the 'cultural property' and the 'tradition' combined, each had different meaning at the beginning. And it investigated the linkage of them which effect to the protection system and to each other on the system operated. Then, it pointed out a rift within the discourse of tradition to which the system have held on, and the problems as its result. This paper applied the viewpoint of anti-essentialism that the tradition is presented with hegemonic act to raise the inevitable continuity with the past, instead of the common notion that the tradition is 'everything that is handed down from the past.' Because the cultural property is the product of the state system, to pursne the linkage of it and the tradition is identical to examine how the tradition have been officially defined in the national hegemony. Since the 1920s the tradition has defined as a fixed, essential, pure reality in the changing process of the protection system of cultural property. This essentialist viewpoint about the tradition have been continued as the institutional premise regardless of many critics, raised by studies focusing on the culture and cultural property. But we see now a rift on the discourse of tradition as the intellectual discourse has been supported to the system, that is caused by the fast-changing global economic environment and a rat race around the registration of intangible cultural heritage of UNESCO.