• Geotechnical Engineering
• /
• v.11 no.2
• /
• pp.29-36
• /
• 1995

Load testis are executed on model reticulated root piles (RRP) to figure out the optimum slanting angle in the piles installation. One set of model RRP consists of 8 slanting piles which are installed in circular patterns forming two concentric circles, each of which is made by 4 piles. Each pile which is a steel bar of 5m in diameter and 300mm in length is coated to become a pile of 6.5mm in diameter. The slanting angle of the model RRP varies from 0$^{\circ}$ to 20$^{\circ}$ Comparing ultimate bearing capacities of the model RRP of different installation angles, it is observed that the ultimate capacities of the RRP increase as the installation angle increases until 15$^{\circ}$, and the optimum slanting angle of the RRP is around 15$^{\circ}$ The ultimate bearing capacity of the 15$^{\circ}$-RRP is found to be 22% bigger than that of the vertical RRP and 120% bigger than that of the circular surface footing whose diameter is same with the circle formed by outer root piles'heads. However, it is noticed that when the slanting angle of the RRP is increased over 15$^{\circ}$, the ultimate capacity starts to be reduced. The ultimate capacity of 20$^{\circ}$-RRP is even smaller than that of the vertical RRP by as much as 5%. From the observation of the load settlement curve obtained during the RRP load tests, it is known that as the slanting angle gets bigger the load -settlement behavior becomes more ductile.

• Resources Recycling
• /
• v.5 no.4
• /
• pp.32-41
• /
• 1996

The objective of this study was to investigate the facton affecting the property of CaCO, farmed from CaClz-Na,CO,-HiOsystem. The effcct of the concentmtlon of reaclants, impurity, the pH of reaction, the addition of sccd crystal, and injectingvelocity af reaclant solution an thc yield oI CaCO; polymorphs. parlide size and whiteness of CaCO, were investigated. Thcmqor resulls are ;o fallows; I The optimum concentratinn of reildilnts for forming vaterlte and aragonite is the range of 0.1-1.0 mol/l, when the yicld of vittcrite and araga~nles howed 7542% and XU-90%. respedively. 2. Among thc composition of impunticscontained h limestone, Fe' decrease the wh~tcness nf CaCO;. md Mg" increase the yield of aragonite. 3. The pHrange of vaterite and aragonite are formed with high yield is 8-11, and Calcite is famed in pH 6-8 with big particle size of 1over and in pH 11-13 with small particle size of I under. 4. The yicld of calcite and aragonite was increased by addingthc seed cryst.al nf itself.d cryst.al nf itself.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.15 no.1
• /
• pp.13-20
• /
• 1985

The author obtained the oblique lateral trans cranial radiograms from 376 patients (114 of male, and 262 of female) with temporomandibular joint arthrosis. After tracing each film, the author analyzed the dimensional changes of the condylar heads with pain, clicking, mouth opening limitation, and masticatory difficulty respectively, which were the chief complaints of the TMJ arthrosis and compared these data with control group. The results were as follows; 1. There was a great predilection for occurrence of the TMJ arthrosis in female (262 cases) over male (114 cases). But there was no significant difference in ratio between the sexes on each symptom. In male, 60 patients (52.6%) had pain, 28 patients (24.6%) had clicking, 21 patients (18.4%) had mouth opening limitation, and 5 patients (4.4%) had masticatory difficulty. In female, 148 parients (56.5%) had pain, 57 patients (21.8%) had clicking, 47 patients (17.9%) had mouth opening limitation, and 10 patients (3.8%) had masticatory difficulty. 2. Examined controlled group, the author analyzed the dimension of W-W', 0-H, 0-A, 0-B on the right side first, and left side second. In male, the dimension of W-W' was 14.52㎜, 14.13㎜; 0-H was 13.92㎜, 13. 71㎜' 0-A was 8.91㎜, 9.0㎜ and 0-B was 8.67㎜, 8.78㎜. In female, W-W' was 13.77㎜, 13.51㎜; 0-H was 13.42㎜, 13.35㎜; 0-A was 8.92㎜, 9.01㎜; and 0-B was 8.59㎜, 8.80㎜. 3. W-W' and 0-H of the experimental group were distinctly lesser than the controlled group. Male with mouth opening limitation show the least (12.70㎜, 13.00㎜) on W-W', but both sexes with pain show the least on 0-H. There was no significant difference between experimental group with Clicking and controlled group on 0-H, 0-A, and 0-B. And also there was no difference on 0-B in patients with every symptom except masticatory difficulty. The dimensional changes of the condylar heads with those symptoms were as follows; a) In male patients, complaing of pain, W-W' of the right and left was 13.80㎜, 12.80㎜; 0-H was 13.10㎜, 12.90㎜; 0-A was 8.69㎜, 8.18㎜; 0-B was 8.33㎜, 8.42㎜. In female, W-W' was 13.01㎜, 12.90㎜; 0-H was 12.48㎜, 12.80㎜; 0-A was 8.60㎜, 8.49㎜; 0-B was 8.48㎜, 8.50㎜. b) In male patients with clicking, W-W' was 13.70㎜, 13.10㎜; 0-H was 13.90㎜, 13.10㎜; 0-A was 8.81㎜, 8.16㎜ 0-B was 8.34㎜, 8.25㎜. In female, W-W' was 13.10㎜, 13.50㎜; 0-H was 13.30㎜, 12.91㎜; 0-A was 8.95㎜, 8.49㎜; 0-B was 8.23㎜, 8.70㎜. c) In male patients with mouth opening limitation, W-W' was 12.70㎜, 13.00㎜; 0-H was 13.40㎜, 13.40㎜; 0-A was 8.37㎜, 8.48㎜; 0-B was 8.33㎜, 8.62㎜. In female, W-W' was 13.00㎜, 12.50㎜ 0-H was 12.90㎜, 13.10㎜; 0-A was 8.49㎜, 8.09㎜; 0-B was 8.77㎜, 8.01㎜. d) In male patients with masticatory difficulty, W-W' was 13.30㎜, 13.20㎜; 0-H was 13.40㎜, 12.60㎜; 0-A was 8.26㎜, 8.32㎜; 0-B was 7.80㎜, 8.20㎜. In female, W-W' was 12.30㎜, 12.00㎜; 0-H was 13.10㎜, 13.20㎜; 0-A was 8.68㎜, 7.95㎜; 0-B was 7.46㎜, 7.87㎜.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.2
• /
• pp.21-31
• /
• 2010

This paper presents a design of PLL and SSCG for reducing the EMI effect at the electronic machinery and tools for DisplayPort application. This system is composed of the essential element of PLL and Charge-Pump2 and Reference Clock Divider to implement the SSCG operation. In this paper, 270MHz/162MHz dual-mode PLL that can provide 10-phase and 1.35GHz/810MHz PLL that can reduce the jitter are designed for 2.7Gbps/162Gbps DisplayPort application. The jitter can be reduced drastically by combining 270MHz/162MHz PLL with 2-stage 5 to 1 serializer and 1.35GHz PLL with 2 to 1 serializer. This paper propose the frequency divider topology which can share the divider between modes and guarantee the 50% duty ratio. And, the output current mismatch can be reduced by using the proposed charge-pump topology. It is implemented using 0.13 um CMOS process and die areas of 270MHz/162MHz PLL and 1.35GHz/810MHz PLL are $650um\;{\times}\;500um$ and $600um\;{\times}\;500um$, respectively. The VCO tuning range of 270 MHz/162 MHz PLL is 330 MHz and the phase noise is -114 dBc/Hz at 1 MHz offset. The measured SSCG down spread amplitude is 0.5% and modulation frequency is 31kHz. The total power consumption is 48mW.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.3 no.1
• /
• pp.26-45
• /
• 1992

This study presents the behavioral and cognitive changes by administration of methylphenidate(MPH) and imipramine(IMI) for the treatment of attention-deficit hyperactivity disorder(ADHD) in $5_{1/2}{\sim}12$ years old children referred to child psychiatric clinics. Behavioral changes are assessed with parent's and teacher's ratings. Drug effects on attention. short-term memory, and impulsivity are evaluated with psychological tests in laboratory. The changes were assessed twice in a 8-week periods. The data were analyzed seperately for 15 subjects each drug using repeated measured analysis of variance(ANOVA). The findings indicates that behavioral and cognitive impairments are improved by both drugs, but impulsivity is not. And MPH is superior to IMI on the improvement of attentional problem ; especially the findings indicates important differences between simple task and complex. perceptual-search task. These data confirm the effectiveness of MPH for treatment of ADHD, also raise questions regarding assessment method of attention and impulsivity as fell as importance of impulsivity in ADHD.

• Korean Journal of Agricultural Science
• /
• v.26 no.2
• /
• pp.77-93
• /
• 1999

This study is aiming at identifying the foreward and backward lingkage effects of the farm land base development project. Korean Government has continuously carried out farmland base development projets including the integrated agricultural development projects. large and medium scale irrigation projects and the comprehensive development of the four big river basin including tidal land reclamation and estuary dam construction for the all weather farming since 1962. the starting year of the five year economic development plans. Consequently the irrigation rate of paddy fields in Korea reached to 75% in 1998 and to escalate the irrigation rate, the Government had procured heavy investment fund from IBRD. IMF and OECF etc. To cope with the agricultural problems like trade liberalization in accordance with WTO policy, the government has tried to solve such problems as new farmland base development policy, preservation of the farmland and expansion of farmland to meet self-sufficiency of foods in the future. Especially, farmland base development projects have been challanged to environmental and ecological problems in evaluating economic benefits and costs where the value of non-market goods have not been included in those. Up to data, in evaluating benefits and costs of the projects, farmland base development projects have been confined to direct incremental value of farm products and it's related costs. Therefore the projects'efficiency as a decision making criteria has shown the low level of economic efficiencies. In estimating economic efficiencies including Leontiefs input-output analysis of the projects could not be founded in Korea at present. Accordingly this study is aimed at achieving and identifying the following objectives. (1) To identify the problems related to the financial supports of the Government in implementing the proposed projects. (2) To estimated backward and foreward linkage effects of the proposed project from the view point of national economy as a whole. To achieve the objectives, Hwangrak benefited area with reservoir which is located in Seosan-haemi Disticts, Chungnam Province were selected as a case study. The main results of the study are summarized as follows : a. The present value of investment and O & M cost were amounted to 3,510million won and the present value of the value added in related industries was estimated at 5.913million won for the period of economic life of 70 years. b. The total discounted value of farm products in the concerned industries derived by the project was estimated at 10,495million won and the foreward and backward linkage effects of the project were amounted to 6,760 and 5,126million won respectively. c. The total number of employment opportunities derived from the related industries for the period of project life were 3,136 man/year. d. Farmland base development projects were showed that the backward linkage effects estimated by index of the sensitivity dispersion were larger than the forward linkage effect estimated by index of the power of dispersion. On the other hand, the forward linkage effect of rice production value during project life was larger than the backward linkage effect e. The rate of creation of new job opportunity by means of implementing civil engineering works were shown high in itself rather than any other fields. and the linkage effects of production of the project investment were mainly derived from the metal and non-metal fields. f. According to the industrial linkage effect analysis, farmland base development projects were identified economically feasible from the view point of national economy as a whole even though the economic efficiencies of the project was outstandingly decreased owing to delaying construction period and increasing project costs.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.1
• /
• pp.16-27
• /
• 2010

Purpose: The aim of this experimental study is to observe the effect of platelet-rich plasma (PRP) on early bone regeneration of rats both in normal condition and in osteoporosis induced by ovariectomy. Material and methods: Total 40 Sprague-Dawley female rats were divided into 4 groups. A 8-mm-diameter calvarial critical-sized defect (CSD) was made by drilling with trephine at the center of calvaria in cranium of every rat. Every CSD was augmented with an osteoconductive synthetic alloplastic substitute ($MBCP^{TM}$) and PRP as follows. Group A; 10 non-ovariectomized rats grafted with only $MBCP^{TM}$. Group B; 10 non-ovariectomized rats grafted with $MBCP^{TM}$ and PRP. Group C; 10 ovariectomized rats grafted with only $MBCP^{TM}$. Group D; 10 ovariectomized rats grafted with $MBCP^{TM}$ and PRP. At 4 weeks after graft, every rat was sacrificed. And histomorphometric analysis was performed by measuring calcified area of new bone formation within the CSD. Results: Comparing four groups, results were obtained as follows. 1. In non-ovariectomized groups, PRP showed a positive effect somewhat but not significant (P > .05). 2. In ovariectomized groups, PRP showed a positive effect significantly (P < .05). 3. In PRP untreated groups, ovariectomy diminished bone regeneration significantly (P < .05). 4. In PRP treated groups, ovariectomy diminished bone regeneration somewhat but not significant (P > .05). Conclusion: Within the limitation of this study, it can be concluded that PRP in combination with an osteoconductive synthetic alloplastic substitute has an effect on bone regeneration more significantly in ovariectomized osteoporotic rats than in normal rats.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2003.04a
• /
• pp.61-62
• /
• 2003

Clonal propagation of high-value forest trees through somatic embryogenesis (SE) has the potential to rapidly capture the benefits of breeding or genetic engineering programs and to improve raw material uniformity and quality. A major barrier to the commercialization of this technology is the low quality of the resulting embryos. Several factors limit commercialization of SE for Corsican pine, including low initiation rates, low culture survival, culture decline causing low or no embryo production, and inability of somatic embryos to fully mature, resulting in low germination and reduced vigour of somatic seedlings. The objective was to develop a Corsican pine maturation medium that would produce cotyledonary embryos capable of germination. Treatments were arranged in a completely randomized design. Data were analyzed by analysis of variance, and significant differences between treatments determined by multiple range test at P=0.05. Corsican pine (Pinus nigra var. maritima) cultures were initiated on modified !P6 medium. Modifications of the same media were used for culture multiplication and maintenance. Embryogenic cultures were maintained on the same medium semi solidified with 2.5 g/l Gelrite. A maturation medium, capable of promoting the development of Corsican pine somatic embryos that can germinate, is a combination of iP6 modified salts, 2% maltose, 13% polyethylene glycol (PEG), 5 mg!l abscisic acid (ABA), and 2.5 g/l Gelrite. After initiation and once enough tissue developed they were grown in liquid medium. Embryogenic cell suspensions were established by adding 0.951.05 g of 10- to 14-day-old semisolid-grown embryogenic tissue to 9 ml of liquid maintenance media in a 250ml Erlenmeyer flask. Cultures were then incubated in the dark at 2022$^{\circ}$C and rotated at 120 rpm. After 2.53 months on maturation medium, somatic embryos were selected that exhibited normal embryo shape. Ten embryos were placed horizontally on 20 ml of either germination medium ($\frac{2}{1}$strength Murashige and Skoog (1962) salts with 2.5 g/l activated charcoal) or same medium with copper sulphate adjusted to 0.25 mg/1 to compensate for copper adsorption by activated carbon. 2% and 4% maltose was substituted by 7.5% and 13% PEG respectively to improve the yield of the embryos. Substitution of' maltose with PEG was clearly beneficial to embryo development. When 2% of the maltose was replaced with 7.5% PEG, many embryos developed to large bullet-shaped embryos. At latter stages of development most embryos callused and stopped development. A few short, barrel-shaped cotyledonary embryos formed that were covered by callus on the sides and base. When 4% of the maltose was removed and substituted with 13% PEG, the embryos developed further, emerging from the callus and increasing yield slightly. Microscopic examination of the cultures showed differing morphologies, varying from mostly single cells or clumps to well-formed somatic embryos that resembled early zygotic embryos only liquid cultures with organized early-stag. A procedure for converting and acclimating germinants to growth in soil and greenhouse conditions is also tested. Seedling conversion and growth were highly related to the quality of the germinant at the time of planting. Germinants with larger shoots, longer, straighter hypocotyls and longer roots performed best. When mature zygotic embryos germinate the root emerges, before or coincident with the shoot. In contrast, somatic embryos germinate in reverse sequence, with the cotyledons greening first, then shoot emergence and then, much later, if at all, the appearance of the root. Somatic seedlings, produced from the maturation medium, showed 100% survival when planted in a field setting. Somatic seedlings showed normal yearly growth relative to standard seedlings from natural seed.

• Education of Primary School Mathematics
• /
• v.16 no.3
• /
• pp.229-250
• /
• 2013

The purpose of this study is analyzing 'observation and recommendation letter by teacher', which is being submitted to screen and enhance the utilization of gifted students in accordance with recently introduced gifted students observation, recommendation and screening system. For the purpose, this study will provide with objective securing plan of 'observation and recommendation letter by teacher' by developing an optimum evaluation model. The research findings were as follows: First, the result of analysis on the mathematically gifted students behavior characteristic as appeared in 'observation and recommendation letter by teacher' suggested that the recommending teachers have the tendency of giving superficial statement instead of giving concrete case description. When it was analyzed for frequency by the 'observation and recommendation letter by teacher' analysis framework devised by the author, the teachers showed the tendency of concentrating on specific questions. Meanwhile, there was a tendency that teachers concentrate on specific gifted behavior characteristic or area for which concrete case had been suggested. The reason is believed that such part is easy to observe and state while others are not, or, teachers did not judge the other part as the characteristic of gifted students. Second, the gifted students behavior characteristics as appeared in 'observation and recommendation letter by teacher' were made into scores by Rubric model. When the interrater reliability was analyzed based on these scores, the correlation coefficient of 1st scoring was .641. After a discussion session was taken and 2nd scoring was done 3 weeks later, the correlation coefficient of 2nd scoring increased to .732. The reason is believed that; i) the severity among scorers was adjusted by the discussion session after the 1st scoring, ii) the scorers established detail judgment standard on various situations which can appear because of the descriptive nature, and, (iii) they found a consensus on scoring for a new situation appeared. It implies that thorough understanding and application of scorers on evaluation model is as important as the development of optimum model for the differentiation of mathematically gifted elementary students.

• Journal of Biomedical Engineering Research
• /
• v.21 no.3 s.61
• /
• pp.321-331
• /
• 2000

Multiple 15-hue tests were designed and implemented on a PC in the study so as to quickly and quantitatively evaluate color vision acuity. Difficulty of the test was control)ed by the value of CDBACC (color difference between adjacent color chips) calculated using a CIELAB formula. The multiple 15-hue tests consist of eight of the hue tests (test 3-10) and three of the basic color (red, green, blue) tests (test 11-13). The 15 colors used for the hue tests were specified by the 15 color coordinates that were located at a constant distance (d = 2. 3. 5. 7, 10, 20, 30. 40) from white reference in the CIE chromaticity coordinate system and were separated by a constant color difference (CDBACC = 0.75, 1.1, 1.8. 2.5. 3.5. 7.5. 11, 14) from the adjacent chips. The color coordinates for the 15 chips for the basic color tests were the same as those of the 15 points spaced equally by a constant color difference (6.87 for the green color test. 7.27 for the red color test, 7.86 for the blue color test) from the white reference along the axis of red, green and blue. Thirty normal subjects who were not color blind were taken to undergo the multiple 15-hue tests. It was observed that most of the subjects correctly arranged color chips for the tests with CDBACC greater than 5, whereas no one correctly answered for those with CDBACC less than 2. Rapid changes in the number of the subjects correctly arranged took place when CDBACC of the tests was between 2 and 4.5. In the basic color tests, unlike the hue tests having similar values of CDBACC, it was seen that the subjects arranged color chips even less correctly. It was found that JNCD (just noticeable color difference) - a measure of color vision acuity was about 3 in average for the subjects. The JNCD was chosen as the value of the CDBACC of the test for which about $50\%$ of the subjects failed to successfully arrange color chips. ERCCA (error rate of color chips arrangement) for the test with CDBACC the same as the JNCD was shown to be about $20\%$. It is expected that the multi 15-hue tests implemented on a PC in the study will be an economical tool to quickly and quantitatively evaluate color vision acuity and, accordingly, the tests can be used for early diagnosis to massive potential patients suffering from diseases (ex. diabetes, glaucoma) which may induce changes in color vision acuity.