• Journal of The Korean Association For Science Education
• /
• v.30 no.7
• /
• pp.901-907
• /
• 2010

The purpose of this study is to analyze methods for measuring the size of the Earth, put forth in 6 different Korean 8th grade science textbooks. The research questions are as follows: 1) Do they adequately map out the experiments for measuring the size of the earth by using the concept of the sun's altitude? 2) Do they reduce the size of the sun like as the Earth is similarly downsized to the globe? 3) Do they suggest the precise experimental conditions for selecting two equal longitudinal spots for measuring the size of the earth? 4) Do they design adequate experiments for exact measurement? 5) Do they offer a proportional expression for seeking the size of globe which is easily understood by students? 6) Do they develop experiments to measure actual size of the earth? Four graduate students and one researcher took part in this study. All conditions were unanimously agreed upon by the participants. The results are as follows. First, one publishing company must include the concept of the sun's altitude to accurately measure the size of the Earth. However, some textbooks fail to mention this. As such, the concept of the sun's altitude must be introduced to accurately measure the size of the Earth. Second, a reduced size globe is used as the actual earth so; the sun should be factored in with a reduced light value. Third, you have to lay a stress on two points at the same longitude. In other words, a shadow located at the same longitude from two randomly selected points. Most textbooks mention two points at the same longitude but two of them design the experiment with a shadow at the same longitude. Fourth, we need a method to precisely measure the angle between a stick and its shadow. The angle between the stick and the tip of its shadow is the sun's altitude difference. Fifth, we need to present more specific proportional expressions for calculating the size of the globe. Only 3 out of the 6 texts employed a proportional expression. Sixth, we need to calculate the size of the earth by accurately presenting the scale of the globe to attain the goal of the experiment. Two of the texts analyzed, designed the experiment for the purpose of calculating the size of the globe. Three of the texts designed their experiments to calculate the radius of globe which is not even relevant to the purpose of experiment.

• Journal of Wetlands Research
• /
• v.15 no.1
• /
• pp.91-103
• /
• 2013

In this Research, in order to improve problems of not enough technical validation and structural and hydraulic stability evaluation when nature-friendly revetment block is applied to field, hydraulic stability evaluation according to hydraulic behavior change of porosity soil block for vegetation reinforcement that secures ecological function was reviewed. By selecting object section, numerical analysis and hydraulic model experiments were performed; for numerical analysis, by using 1-dimensional numerical analysis model HEC-RAS and 2-dimensional numerical analysis RMA-2, one-dimensional(1D) and two-dimensional(2D) numerical analysis were performed; by applying Froude's similarity law, reduced-scale hydraulic model experiments according to vegetation existence were performed. In hydraulic model experiment, for validity of experiment result, the result of velocity and tractive force of reduced-scale hydraulic model experiments was converted to prototype so that it can be compared and reviewed under the same condition of one-dimensional(1D) and two-dimensional(2D) numerical analysis result; as a result, it was confirmed that comparatively united result appeared, and by comparing prototype-converted tractive force result with revetment's allowable tractive force coming from an existing research, block's hydraulic stability was suggested.

• Journal of Society of Preventive Korean Medicine
• /
• v.13 no.3
• /
• pp.101-112
• /
• 2009

Objectives : This comparative study aimed to identify the effect of the Buddeumi(cupping-and-moxibustion device) therapy and moxibustion-only therapy on treating constipation of stroke patients who were admitted in the hospital of oriental medicine. The research design was a nonequivalent control group pretest-posttest design. Methods : The subjects of the study consisted of 23 stroke patients, and they were divided into two groups : one was the experimental group of 11 patients and the other was the control group of 12 patients. The Buddeumi therapy and the moxibustion-only therapy were given respectively. Each Buddeumi and moxibustion-only therapies on the 天樞(ST25, right & left) in abdomen were administered to the each group for 40 minutes a total at 10 times. The posttest included the frequency of defecation with the Constipation Assessment Scale every day for one week after the experiment. The data were analyzed by the $x^2$ test, t-test, Fisher exact test, and repeated measures ANCOVA using SPSS/WIN 12.0 program. Results : The results were as follows : First, Hypothesis 1 : 'The patients who are given the Buddeumi therapy in the experimental group have a lower Constipation Assessment Scale than the control group.' was supported(F=4.367, P=0.049). Second, Hypothesis 2 : 'The patients who are given meridian acupressure in the experimental group have a higher frequency of defecation per week than the control group.' was supported(F=0.947, P=0.034). Accordingly, 'The patients who are given the Buddeumi therapy in experimental group have a higher effect on constipation than the control group.' was supported. Conclusion : The Buddeumi therapy reduced the constipation assessment scale of stroke patients and increased the frequency of their defacation per week. Therefore, the Buddeumi therapy could be an effective treatment for constipation of stroke patients.

• International Journal of Highway Engineering
• /
• v.17 no.6
• /
• pp.105-115
• /
• 2015

PURPOSES : This study aimed to evaluate the appropriateness of safety with the standard for threshold zone luminance as specified in the Recommendation for Lighting of Traffic Tunnel, which has been widely adopted worldwide. METHODS : A driving test of the subject in a full-scale road tunnel was conducted. The adaptation luminance and threshold zone luminance, which should be known for the driver to perceive an object within stopping sight distance, were obtained. These values were compared with the adaptation luminance and threshold zone luminance obtained by the existing reduced model test and tunnel lighting standard that has served as a guideline for the current threshold zone luminance standard. RESULTS : According to this study, threshold zone luminance should be increased to at least 1.8 times the value proposed in the existing studies and to twice the domestic tunnel lighting standard (KS C 3703: 2014). CONCLUSIONS : The threshold zone luminance proposed in this study differs largely from that obtained from indoor tests and from the current tunnel lighting standard used worldwide; this difference may be attributed to the fact that the indoor tests did not incorporate driving workload, non-uniformity of luminance distribution in terms of sight, and factors that reduce the visibility of the driver, such as the light reflected into the driver's eyes. Hence, it is necessary to further review the factors that reduce the visibility of drivers approaching tunnels in order to determine the rational tunnel threshold zone luminance.

• Journal of IKEEE
• /
• v.24 no.2
• /
• pp.426-434
• /
• 2020

FMI is being researched as a standard for linking large-scale simulation of CPS. In order to guarantee the reliability of the results in large-scale simulations using FMI, event handling through time management techniques is required. This paper aims to guarantee real-time performance and accuracy in large-scale co-simulation environments such as CPS. Synchronize the wallclock time and simulation time to ensure real time. Also, to ensure the accuracy, before the simulation, the event is checked and the simulation is performed with the smallest step size while maintaining the real time until the event occurrence time. As a result, the events occurring in the co-simulation environment are processed immediately and sequentially, ensuring the real-time performance and minimizing the numerical integration error by maximizing the simulation resolution. In the experiment, the proposed method was processed immediately, and it was confirmed that the numerical integration error is reduced by about 1/5 unlike the existing time management method which does not guarantee the resolution.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.5
• /
• pp.160-170
• /
• 2003

A pilot study was performed to examine the feasibility of intermittent slow sand filtration for agricultural reuse of reclaimed water. The effluent of biofilter for 16-unit apartment was used as influent to the slow sand filtration system at 0.6 $m^3$/day loading rate using 15 seconds spray in every 10 minutes on the about 1 $m^2$ surface area and 0.5 m depth. The influent concentrations of total coliform (TC), fecal coliform (FC) and E. coli were in the range of 10.000 MPN/100 mL. and they were reduced to less than 1,000 MPN/100 mL after filtration with average of 320, 270, and 154 MPN/100 mL, respectively, showing over 95 % removal. Turbidity and SS were improved effectively and their average concentration was reduced to 0.8 NTU and 1.7 mg/L, respectively, and removal rate was about 50 %. Average BOD and COD concentrations were also reduced substantially to 2.6 and 25.8 mg/L with about 55 and 21 % removal rate, respectively. Nutrients removal was relatively low and removal rate for T-N and T-P was low however, remaining nutrients might be beneficial and less concerned in case of agricultural reuse. The concentration of biofilter effluent used in this experiment was in the range of secondary treatment effluent but slightly stronger than the one from existing wastewater treatment plants (WWTPs). Therefore, intermittent slow sand filtration might be also applicable to the effluent from WWTPs as long as its agricultural reuse is available. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, the intermittent slow sand filtration was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper is a preliminary result from pilot study and further investigations are recommended on the optimum design parameters before full scale application.

• The Korean Journal of Elementary Counseling
• /
• v.4 no.1
• /
• pp.191-214
• /
• 2005

This study aimed to examine the effect of Cyber Group Counseling on the depression of internet addiction children in elementary school. In this study, the following questions were posed: How effective is the Cyber Group Counseling on the depression of internet addiction children? In this study, subjects were 24 students who got 14 points over in KAIS and got 11 points over in CDI among 245 of 5th, 6th grade students in Daegu and Chongdo Kyungbuk who did Internet addiction scale for Korean Adolescent(KAIS) and Children's Depression Inventory(CDI). They were divided into experimental group and comparative group. Subjects in experimental group practiced Cyber Group Counseling for 12 sessions(60 minutes per session) for 6 weeks. But the control group had no treatment during the period. During the experiment, 2 of each groups were left out. The counseling schedule and hor· to join the Cyber Group Counseling clinic were notified by e-mail. The Cyber Group Counseling was on every Monday and Thursday. The Cyber Group Counseling progressed by internet chatting, bulletin board, e-mail and a slip paper counsel. The collected data were analyzed with SPSS/PC+ (statistical package for the social science/personal computer) program and t -test. The findings of this study were as follows: First, the depression of internet addiction children who joined in Cyber Group Counseling was significantly reduced than the others. So, Cyber Group Counseling was proved one of the useful psychotherapy approach. Second, the subordinate of depression including behavioral disturbance and anhedonia was significantly reduced. Third, the subordinate of depression including the dysphoric mood, the self-deprecation and physiological symptoms was reduced. But it was not statistically significant.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1818-1822
• /
• 2008

Generally, not only in order to design three dimensional hydraulic structures such a spillway and to investigate the hydraulic phenomena concerning hydraulic facilities, but also to grasp shape and stability, we simulate actuality phenomenon through hydraulic model experiments. However, it requires too much times, expense and space to perform hydraulic model experiments, as well as it is very difficult to measure reduced scale of actual hydraulic structures. Besides, surface tension can exert fair effect in experiment result, and occasionally an experiment of various case is impossible actually. Therefore, there is necessity to draw proper early result through numerical analysis, and if decide the case of a hydraulic model experiment through the numerical analysis and compare the result, finally economical and reasonable design hydraulic structures are available. This study performs numerical analysis of overflow spillway and an experimental study of hydraulic model tests to design the optimal spillway and suggest a better design to improve hydraulic conditions. From the measurements, revised designs for an hydraulic structure are suggested and consequent improvement effects by the new design are also investigated.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.5
• /
• pp.54-63
• /
• 2007

To examine the effects of amendments on heavy mineral oil degradation, a pilot scale experiment was conducted for over 105days. During the experiment, soil samples were collected and analyzed periodically for the determination of residual hydrocarbon and microbial activities. At the end of the experiment, the initial level of contamination ($6,205{\pm}173mgkg^{-1}$) was reduced by $33{\sim}45%$ in the amendment amended soil; whereas only 8% of the hydrocarbon was eliminated in the non-amended soil. Heavy mineral oil degradation was much faster and more complete in compost amended soils. Enhanced dissipation of heavy mineral oil in compost amended soil might be derived from increased microbial activities (respiration, microbial biomass-C) and soil enzyme activity(lipase, dehydrogenase, and FDA hydrolase) were strongly correlated with heavy mineral oil biodegradaton (P < 0.01).

• Applied Biological Chemistry
• /
• v.8
• /
• pp.45-50
• /
• 1967

Starch was liquefied by the bacteriological ${\alpha}-amylase$ and saccharified separately by four strains of mold as saccharogenic enzymes, then thise was fermented for research the fermentation rates, the usefulness of application of four strains of mold and the S.P to need in proportion increasing of concentration of mixed-starches for brewing in this experiment. The obtained results were as follows: 1) In the ability of saccharificatien, fermentation and acid resistance, Aspergillus usamii mut shirousamii, which were used to produce the koji, were excellent, however, Rhizopus delemar had heavy pollution in a lot of production of koji, were-as its qualities as enzyme was good. 2) The necessary S.P in proportion to the concentration of mixed-starch for brewing was found in this experiment in which was fermented in the various concentration of the adding S.P and the mixed-starches for brewing. 3) In the experiment of almost manufacture scale, the S.P needed essentially in the saccharogenic formentation was found and the usefulness of the necessary S.P was observed, and in fact in the manufacture scale it was safer to add the S.P more than 1.2% because it must be considered that the ability of enzymes is reduced by heat or acid. 4) The period of fermentation was shorten because the conditions for yeast propagation were excellent as a results of starches being liquefied by bacteriological amylase, and saccharified by molds as saccharogenic enzymes.