• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.4
• /
• pp.109-119
• /
• 2004

Rapid prototyping (RP) technologies have been widely used to reduce the lead-time and development cost of new products. $VLM-_{ST}$ process has been developed to overcome the currently developed RP technologies such as a large building time, a high building cost, an additional post-processing and a large apparatus cost. $VLM-_{ST}$ process requires an additional human interaction due to the manual stacking and bonding. Hence, building time, building cost and the part quality are dependent on the skill of labor. A novel RP process, fully automated $VLM-_{ST}$ process ($VLM-_{ST}$), has been developed to improve building efficiency of the process and the human dependency of the part. The objective of this work is to propose a $VLM-_{ST}$ process and to develop an apparatus for implementation of the process. $VLM-_{ST}$ process and its apparatus have various technical novelties such as two step cutting using a rotating table, an automatic stacking method using two pilot holes and two reference shapes, a concept of automatic unit shape layer (AUSL), and an automatic bonding using the bonding roller and building magazine. In order to examine the efficiency and the applicability of the proposed process, various three-dimensional shapes, such as a piston, a human head shape and a human bust shape, were fabricated on the apparatus.

• Journal of Korean Library and Information Science Society
• /
• v.33 no.2
• /
• pp.167-187
• /
• 2002

This study suggests a plan of tables of deference for Korean Decimal Classification, 4th edition, based on the study on those in Dewey Decimal Classification, 21st edition. It suggests two tables for the Auxiliary Tables, one for standard subdivisions and one for subdivisions for literature. Twenty-two tables are suggested for the Schedule of ten main classes.

• Journal of Nutrition and Health
• /
• v.40 no.1
• /
• pp.89-96
• /
• 2007

This study was performed to weigh the average meal portion sizes served for preschoolers by kindergarten teacher. The subjects were 53 teachers from 8 kindergartens, which are random sampled by meal service number. Using the weighing method assessed the meal portion sizes of food items at lunch. The data was complied by performing $\chi^2-test$ using SPSS WIN 11.0. The result was as followed: 98.0% of teacher agreed with the meal service because of 'better food habit and table etiquette'(68.0%), 'health promotion with balanced diet'(22.0%), 'owing to extending school time'(6.0%) and 'demand of parents'(2.0%). Preschooler eat lunch at class (84.9%) and meal serving size was decided by teacher (79.2%). Teachers thought that they know very well about portion size 3.8%, 96.2% of teacher thought that they don't know much about portion size. Portion size were not significantly different by food tray types but there was much different (almost 100%) compared with minimum and maximum within dishes. Most average portion size was not met dietary reference intake except cooked rice, soups and fish cutlet. Working experience effected on portion size. More served, more working experienced of teacher. For example Bulgogi was served 26.8 g by teacher who has over 6 years working experience compared with 2-6 years (20.4 g) and less than 2 years (17.1 g) (p < 0.01). Spinach portion size was significantly different by teacher's working experience (p < 0.01). Portion size were not significantly different by preschooler's age. The reference of dietary for preschooler was different by age, but teachers served meal by their experience. According to the results of this study, it is necessary to educate meal portion size for kindergarten teacher who take charge in meal serving. To provide guidance to teacher about reasonable portion sizes for preschoolers, teacher need to take nutrition education about meal service and child nutrition in college. This study would be useful to those who plan meals for preschoolers and to researchers studying dietary intakes of preschooler.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.3
• /
• pp.263-272
• /
• 1998

This paper presents the new control strategy that can minimizes the torque ripple by considering the magnetic nonlinearity and phase torque averlapping intervals, and describes the whole SRM drive system using proposed control method implemented by DSP(Digital Signal Processor). To do this, inductance and torque are, at first, measured according to the variation of rotor position angle while current is kept constant at predetermined several values. From these measured values, the entire inductance and torque for any current and rotor position are inferred by using neural network. And the waveform of the reference phase torque is determined for the torque ripple to be minimized considering the torque overlap between phases. The controller is designed for the actual torque obtained by the inferred torque look-up table using measured current and rotor position angle to track the predetermined reference phase torque by delta modulation technique. To perform a real time processing and ensure the reliability of the controller, DSP is implemented.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.1029-1034
• /
• 2010

In this paper, we present the roundness profile and run-out error measurement for a rotating shaft. The devices for measuring the roundness require a precision rotation table which is used as a reference to obtain the circular profile. Therefore, the roundness measuring system is expensive and requires precision manufacturing. The two-point method for succession measurement has been used to obtain a linear profile or used in straightness measurement using two displacement measuring devices. In this paper, the method is used for measuring the circular profile of a rotating shaft. A method to remove the vibration of the shaft, i.e., the run-out, is used, and the original circular profile is obtained from the measured raw data that excludes the run-out error of the rotating shaft. This method will be useful for obtaining the precise circular profile without using a precision reference circular artifact.

• Journal of the Korea Concrete Institute
• /
• v.27 no.5
• /
• pp.511-519
• /
• 2015

Methods such table flow, slump and outflow time have used to be as a main evaluation criteria regards to fluidity of concrete. Since those methods mentioned above have some inaccuracies which are up to its condition of test. Studies that evaluate fluidity applying the rheology has increased its portion in this field. Meanwhile, demands for AAS binder have been increased in accordance with its demand for this market, studies for rheology of AAS binder are little though. Therefore, this paper mainly deals a rheological peculiarity of AAS binder according to its condition of W/B ratio and alkali activators. The fluidity of AAS paste was evaluated with the index of table flow and outflow time. And shear stress following its shear rate was analyzed through rheological test. Rheological parameters were deduced through this rheological test of Bingham model and analyzed its interrelation with fluidity test. As the final outcome, it proposed the interrelation among table flow, yield stress, viscosity and outflow time. In basis of this study, we would like to suggest a reference for mixing AAS mortars and concretes.

• Journal of Nutrition and Health
• /
• v.45 no.1
• /
• pp.80-93
• /
• 2012

Recent studies have reported that the glycemic index (GI) has an effect on developing the risk for metabolic abnormalities such as diabetes, dyslipidemia, and obesity. As there are no reliable GI values for common Korean foods, only a few studies have been carried out using the dietary GI for Korean adults. The aim of this study was to establish a table of GI values for common Korean foods and evaluate dietary glycemic index (DGI) and dietary glycemic load (DGL) among the Korean adult population. International tables of GI values and other published values were used to tabulate GI values for common Korean foods. Among 653 food items, 149 (22.8%) were adapted from published data, 60 (9.2%) were imputed from similar foods, and 444 (68.0%) were assigned a zero. Data from 7,940 subjects aged 20 years and older in the 2007-2008 Korea National Health and Nutrition Examination Survey were obtained, and DGI and DGL were calculated. The average DGI was 60.0 and the average DGL was 182.5 when the reference food GI value was glucose. After adjusting for potential confounding variables, DGI and DGL increased significantly according to age group (p for trend < 0.001). The food group that contributed most to DGL was grain and its products supplying 85.3% of total DGL, whereas the mean GI value in grain and its products was 72.6. Fruits and potatoes also contributed to DGL (5.8 and 2.9%, respectively), and their GIs were high (67.7 for potatoes and 45.8 for fruits). For individual food items, white rice supplied 66.7% of total GI followed by glutinous rice (2.3%) and steamed white rice cakes (2.0%). In conclusion, a table of GI values for 653 common food items was established in which white rice was the most contributing item to DGL. Our results will be useful to examine the relationships between DGI, DGL, and metabolic abnormalities in the Korean population.

• Korean Journal of Health Education and Promotion
• /
• v.13 no.2
• /
• pp.130-166
• /
• 1996

As compared with body height and body weight by ages and sexes, by means of the data reported under other researchers from 1967 to 1994 for 33 years, this study obtained the estimate value of body height and body weight by ages and sexes for the same period, and figured out prediction value of body height and body weight in the ages of between 6 and 14 from 1995 to 2000. These surveys and measurements took for one year from October 1st 1994 to September 30th. As shown in the 〈Table 1〉, in order to calculate the establishment, estimate value and prediction value of the chronological regression model of body height and body weight, by well-grounded 17 representative research papers, this research statistically tested propriety of liner regression model by the residual analysis in advance of being reconciled to simple liner regression model by the autonomous variable-year and the subordinate variable-body weight and measured prediction value, theoretical value from 1962 to 1994 by means of 2nd or 3rd polynomial regression model, with this redult did prediction value from 1995 to 2000. 1. Chronological Change of Body Height and Body Weight The analysis result from regression model of the chronological body height and body weight for the aged 6 - 16 in both sexes ranging from 1962 to 1994, corned from the 〈Table 2-20〉. On the one hand, the measurement value of respective researchers had a bit changes by ages with age growing, but the other hand, theoretical value, prediction value showed the regular increase by the stages and all values indicated a straight line on growth and development with age growing. That is, in case of the aged 6, males had 109.93cm in 1962 and females 108.93cm, but we found the increase that males had 1I8.0cm, females 1I3.9cm. In theoretical value, prediction value, males showed the increase from 109.88cm to 1I7.89cm and females from 109.27cm to 1I5.64cm respectively. There was the same inclination toward all ages. 2. Comparision to Measurement Value and Prediction Value of Body Height and Body Weight in 1994 As shown in the 〈Table 21〉, in case of body height, measurement value and prediction value of body height and body weight by ages and sexes almost showed the similiar inclination and poor grade, in case of body weight, prediction value in males had a bit low value by all ages, and prediction value in females had a high value in adolescence, to the contrary, a low value in adult. 3. Prediction Value of Body Height and Body Weight from 1995 to 2000 This research showed that body height and body weight remarkably increased in adolescence but slowly in adult. This study represented that Korean physique was on the increase and must be measured continually hereafter.

• Journal of Korean Society of Forest Science
• /
• v.106 no.2
• /
• pp.267-273
• /
• 2017

This study was conducted to construct a empirical yield table for Pinus densiflora in real forest. Since existing normal yield tables have been derived by studying and analyzing communities in ideal environment for tree growth, those tables provide more over-estimated values than ones from real forest. Because of this, there are some difficulties to apply the tables to empirical forest except for normal forest. In this study, therefore, we estimated stand growth for real forest on P. densiflora as the representative species of conifers. We used 1,957 sample plot data of P. densiflora in central Korea from National Forest Inventory (NFI) system, and analyzed through estimation, recovery and prediction in order by using Weibull function as a diameter distribution model. Weilbull and Schumacher models were applied for estimating mean DBH and mean basel area and it was found that the site index for P. densiflora in central Korea ranges from 8 to 14 at reference age 30. According to site 12 in the stand yield table, the Mean Annual Increment (MAI) of P. densiflora was $4.42m^3/ha$ at 30 years of age. Compared to existing volume table constructed before, it is showed that MAI of this study were lower. According to the paired t-test that is conducted with the gap of volume values between normal forest and real forest by site index and age, the P-value was less than 0.001 which is recognized to have a statistically significant difference. Based on the results in this study, it is considered to be helpful for practical management and management policy on P. densiflora in central Korea.

• Journal of the Korea Institute of Building Construction
• /
• v.22 no.6
• /
• pp.619-630
• /
• 2022

The concrete mix design and compressive strength evaluation are used as basic data for the durability of sustainable structures. However, the recent diversification of mixing factors has created difficulties in calculating the correct mixing factor or setting the reference value concrete mixing design. The purpose of this study is to design a predictive model of bidirectional analysis that calculates the mixing elements of ternary concrete using deep learning, one of the artificial intelligence techniques. For the DNN-based predictive model for calculating the concrete mixing factor, performance evaluation and comparison were performed using a total of 8 models with the number of layers and the number of hidden neurons as variables. The combination calculation result was output. As a result of the model's performance evaluation, an average error rate of about 1.423% for the concrete compressive strength factor was achieved. and an average MAPE error of 8.22% for the prediction of the ternary concrete mixing factor was satisfied. Through comparing the performance evaluation for each structure of the DNN model, the DNN5L-2048 model showed the highest performance for all compounding factors. Using the learned DNN model, the prediction of the ternary concrete formulation table with the required compressive strength of 30 and 50 MPa was carried out. The verification process through the expansion of the data set for learning and a comparison between the actual concrete mix table and the DNN model output concrete mix table is necessary.