• Journal of Environmental Health Sciences
• /
• v.43 no.3
• /
• pp.223-232
• /
• 2017

Objectives: In response to increased interest in the safety of children's products, a risk management system is being prepared through exposure assessment of hazardous chemicals. To estimate exposure levels, risk assessors are using deterministic and probabilistic approaches to statistical methodology and a commercialized Monte Carlo simulation based on tools (MCTool) to efficiently support calculation of the probability density functions. This study was conducted to analyze and discuss the usage patterns and problems associated with the results of these two approaches and MCTools used in the case of probabilistic approaches by reviewing research reports related to exposure assessment for children's products. Methods: We collected six research reports on exposure and risk assessment of children's products and summarized the deterministic results and corresponding underlying distributions for exposure dose and concentration results estimated through deterministic and probabilistic approaches. We focused on mechanisms and differences in the MCTools used for decision making with probabilistic distributions to validate the simulation adequacy in detail. Results: The estimation results of exposure dose and concentration from the deterministic approaches were 0.19-3.98 times higher than the results from the probabilistic approach. For the probabilistic approach, the use of lognormal, Student's T, and Weibull distributions had the highest frequency as underlying distributions of the input parameters. However, we could not examine the reasons for the selection of each distribution because of the absence of test-statistics. In addition, there were some cases estimating the discrete probability distribution model as the underlying distribution for continuous variables, such as weight. To find the cause of abnormal simulations, we applied two MCTools used for all reports and described the improper usage routes of MCTools. Conclusions: For transparent and realistic exposure assessment, it is necessary to 1) establish standardized guidelines for the proper use of the two statistical approaches, including notes by MCTool and 2) consider the development of a new software tool with proper configurations and features specialized for risk assessment. Such guidelines and software will make exposure assessment more user-friendly, consistent, and rapid in the future.

• Journal of the Korea Concrete Institute
• /
• v.14 no.6
• /
• pp.813-822
• /
• 2002

The purpose of the present study is first to refine the mathematical material models for moisture and temperature distributions in early-age concrete and then to incorporate those models into finite element procedure. The three dimensional finite element program developed in the present study can determine the degree of hydration, temperature and moisture distribution in hardening concrete. It is assumed that temperature and humidity fields are fully uncoupled and only the degree of hydration is coupled with two state variables. Mathematical formulation of degree of hydration Is based on the combination of three rate functions of reaction. The effect of moisture condition as well as temperature on the rate of reaction is considered in the degree of hydration model. In moisture transfer, diffusion coefficient is strongly dependent on the moisture content in pore system. Many existing models describe this phenomenon according to the composition of mixture, especially water to cement ratio, but do not consider the age dependency. Microstructure is changing with the hydration and thus transport coefficients at early ages are significantly higher because the pore structure in the cement matrix is more open. The moisture capacity and sink are derived from age-dependent desorption isotherm. Prediction of a moisture sink due to the hydration process, i.e. self-desiccation, is related to autogenous shrinkage, which may cause early-age cracking in high strength and high performance concrete. The realistic models and finite element program developed in this study provide fairly good results on the temperature and moisture distribution for early-age concrete and correlate very well with actual test data.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.12
• /
• pp.1792-1797
• /
• 2012

The feasibility of incorporating jujube powder as a value-added food ingredient in bakery food products, using a model system of muffins, was investigated. Jujube powder was incorporated into muffins at 0, 5, 10, 15, and 20% weight amounts based on the total weight of wheat flour. Qualities, such as pH, volume index, height, and moisture content, of muffins decreased significantly with increasing levels of jujube powder added (p<0.05). In terms of color, lightness decreased, whereas redness increased significantly for both crust and crumb (p<0.05) with increasing levels of jujube powder. Baking loss also decreased gradually, while hardness and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were significantly influenced with higher amounts of jujube powder in the formulation (p<0.05). Finally, the consumer acceptance test indicated that the highest levels of jujube incorporation (20%, w/w) had a considerable adverse effect on consumer preferences in all attributes. In contrast, muffins with moderate levels of jujube powder (10%, w/w) are recommended (with respect to overall preference score) for taking advantage of the functional properties of jujube powder without sacrificing consumer acceptability.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.7
• /
• pp.1077-1081
• /
• 2016

Feasibility of incorporation of licorice powder (LP) as a value-added food ingredient into convenient food products was investigated using yanggaeng as a model system. LP was incorporated into yanggaeng at amounts of 0, 2, 4, 6, and 8% (w/w) based on total weight of cooked white beans and LP. pH level decreased while soluble solid content significantly increased with increasing levels of LP (P<0.05). In terms of color, lightness decreased while redness and yellowness increased significantly (P<0.05) with increasing levels of LP. Hardness also decreased significantly with a higher amount of LP in the formulation (P<0.05). 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activities were significantly elevated by LP addition, and they increased significantly as LP concentration increased in the formulation (P<0.05). Finally, consumer acceptance test indicated that the highest levels of LP incorporation (8%) had an adverse effect on general consumer preferences. In contrast, yanggaeng with moderate levels of LP (2%) is recommended based on its overall scores to take advantage of the antioxidant properties of LP without sacrificing consumer acceptability.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.29 no.1
• /
• pp.11-19
• /
• 2005

Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bacause of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, caused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of developement such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

• The KIPS Transactions:PartB
• /
• v.8B no.5
• /
• pp.429-440
• /
• 2001

To achieve a computer tutor framework with high learning effects as well as practicality, the goal of this research has been set to developing an intelligent tutor for problem-solving in mathematics domain. The maine feature of the CyberTutor, a computer tutor developed in this research, is the facilitation of a learning environment interacting in accordance with the learners differing inferential capabilities and needs. The pedagogical information, the driving force of such an interactive learning, comprises of tutoring strategies used commonly in various domains such as phvsics and mathematics, in which the main contents of learning is the comprehension and the application of principles. These tutoring strategies are those of testing learners hypotheses test, providing hints, and generating explanations. We illustrate the feasibility and the behavior of our propose framework with a sample problem-solving learning in geometry. The proposed tutorial framework is an advancement from previous works in several aspects. Firstly, it is more practical since it supports handing of a wide range of problem types, including not only proof types but also finding-unkown tpes. Secondly, it is aimed at facilitating a personal tutor environment by adapting to learners of varying capabilities. Finally, learning effects are maximized by its tutorial dialogues which are derived from real-time problem-solving inference instead of from built-in procedures.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.1A
• /
• pp.93-98
• /
• 2004

Serial ATA interface Is inexpensive comparatively and performance is superior. So it is suitable technology in demand that now require data transmission and throughput of high speed. This paper describes a design and implementation of Serial ATA Link layer about error detection and 8b/10b encoder/decoder for DC balance in frequency 150MHz. The 8b/10b Encoder is partitioned into a 5b/6b plus a 3b/4b coder. The logical model of the block is described by using Verilog HDL at register transistor level and the verified HDL is synthesized using standard cell libraries. And it is fabricated with $0.35{\mu}m$ Standard CMOS Cell library and the chip size is about $1500{\mu}m\;*\;1500{\mu}m$. The function of this chip has been verified and tested using testboard with FPGA equipment and IDEC ATS2 test equipment. It is used to frequency of 100MHz in verification processes and supply voltage 3.3V. The result of testing is well on the system clock 100MHz. The designed and verified each blocks may be used IP in the field of high speed serial data communication.

• Journal of the Korean Data and Information Science Society
• /
• v.27 no.3
• /
• pp.749-761
• /
• 2016

The purpose of this study was to investigate the effects of emotional regulation between clinical practice stress and nursing professionalism in nursing students. Participants were 192 nursing students and data were collected from September to November, 2015. This study has shown that nursing professionalism is negatively associated with clinical practice stress (r=-.40, p<.001) and positively associated with emotional regulation (r=.55, p<.001). In addition, a negative correlation has been found significant between emotional regulation and clinical practice stress (r=-.20, p<.001). In a final model of hierarchial multiple regression, professor support (${\beta}=.19$, p<.01), satisfaction with nursing as a major (${\beta}=.14$, p<.05), clinical practice stress (${\beta}=-.19$, p<.01) and emotional regulation (${\beta}=.32$, p <.001) were associated with nursing professionalism. In this study, we also have shown that emotional regulation does not play a moderating role on the relationship between clinical practice stress and nursing professionalism. The results of this study suggests that, in order to improve nursing professionalism, it is important to promote support system, develop clinical-practice-stress-relief programs, and enhance emotional regulation training for nursing students.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.5
• /
• pp.49-58
• /
• 2010

The traffic signal controllers being used in the domestic currently are being manufactured based on the korean national police standard which was developed for controlling the quad-light traffic signal having the red, yellow, left-turn arrow, and green lights. But according to the national policy for the traffic operation, they have to be changed to be able to switch the tri-light signal having red, yellow and green lights. In this study, a new tri-light traffic signal controller was designed and developed by the way improving the Signal Control Unit of the existing quad-light standard traffic controller. The Load Signal Unit(LSU) was improved to output 6 signals which are the two assemblies of three signal indications having the red, yellow, and green lights. To enough traffic signals output to control each directional movements and the various transport modes which are car, bus, bike, and pedestrian etc., the connector bus system was designed to be able to accommodate maximum 96 signals outputs being constructed by 16 LSUs. Flasher device was developed to be able to support maximum 32 red signals. In the software, the communication protocol between traffic control center and the traffic signal controller was improved and new signal map code values were defined for the developed LSU controlling the quad-light traffic signal. A model of the quad-light traffic signal controller developed and was tested three operations, protocol-operation, remote-command and control-mode. The test result operated all of them successfully.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.4
• /
• pp.650-654
• /
• 2013

The feasibility of incorporating cinnamon as a value-added food ingredient in bakery food products was investigated using sponge cakes as a model system. Cinnamon powder was incorporated into sponge cakes at 0, 1, 2, 3, or 4% weight amounts, based on the total weight of wheat flour. Cake qualities, such as pH, moisture content, specific volume, and baking loss, decreased significantly with increasing levels of cinnamon powder added (p<0.05). In terms of color, lightness and yellowness decreased, with increasing levels of cinnamon powder. Redness significantly increased for crumb, but decreased for crust (p<0.05) with increasing levels of cinnamon powder. Hardness also significantly increased (p<0.05), while total polyphenol content significantly increased, up to a 2% addition of cinnamon powder, and gradually increased afterwards. Finally, the consumer acceptance test has indicated that higher levels of cinnamon incorporation (2% or higher, w/w) have a considerable adverse effect on consumer preferences in all attributes. In contrast, sponges cakes with a minimal level of cinnamon powder (1%, w/w) are recommended for taking advantage of the functional properties of cinnamon powder without sacrificing consumer acceptability.