• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.4
• /
• pp.519-531
• /
• 2003

Statement of problem : Chronic implant screw loosening remains a problem in restorative practices. Some implant manufactureres have introduced abutment screws with treated material, surfaces and macrostructures in an effort to reduce potential loosening. Purpose : This study evaluated the materials and loading cycles on detorque value after dynamic continous fatigue test in the sinulated conditions of posterior single restoration. Material and method : Fourteen of each of the following abutment screws - titanium alloy, gold alloy, gold-tite, and titanium alloy modified - were used in test. SEM is used to verify macrostructures of each screws. $ZrO_2/Al_2O_3$ composite abutment was tightened on $4{\times}10.0mm$ titanium external implant at 30 Ncm. Cyclic loading machine delivered dynamic loading forces between 20 and 320N for 100,000, 200,000, 300,000, 500,000, and 1,000,000 cycles at frequencies 14Hz. Torque and detorque value after loading was measured. Results : All measued screws had different screw length and thread form. Titanium modified screw had greater detorque value than others before and after cyclic loadings(p<0.05). All abutment screws had no significant change in mean percentage of detorque value after loading to initial value after less than 500.000 cyclic loadings, but significant lower value after 1,000,000 cycles(p<0.05). Conclusion : Within limintations of this study all abutment screws may be loosend after about 1 year use. Annual check-up is nessasary to prevent screw loosening.

• Journal of Korean Society of Rural Planning
• /
• v.16 no.3
• /
• pp.87-101
• /
• 2010

This research has a significance on providing basic material of landscape ecological planning and open space planning of the future site by selecting Sinseo innovative city area, large residential land development district in rural area, by classifying biotope types and implementing recreational value assessment in the level of area. First of all, as a result of classification of biotope types in research site, total 11 biotope type groups including stream biotope and its subordinate 51 biotope types. Also, as a result of the first value assessment of classified biotopes, there are total 5 types such as vegetation-full natural river, fallow ground in I grade. In addition, it is analyzed that grade II have 18 types, III are 10, IV are 12, the least valuable V are 6. Especially, grassland biotope(GD) was classified into grade II, which is one grade raised, because it is analyzed that it has high value in terms of normal access and availability although it was assessed as grade ill in terms of natural experience quality. Lastly, as a result of the second assessment, special areas for natural experience and recreation(1a, 1b) are 15, areas for natural experience and recreation(2a, 2b, 2c) are 47. Especially, the 52th drawing mark space was grade II in the first assessment but its value grade was upgraded because of its high value in terms of use evidence, size of the area, accessibility with housing area, history and cultural character and so on.

• The Journal of the Korea Contents Association
• /
• v.16 no.11
• /
• pp.456-463
• /
• 2016

This study investigates the relationship between the digital music service acceptance factors on the Perceived value, and Customer Satisfaction. Remarkable points of this study are as follows. First, according to the result of the analysis of relationship between digital music service acceptance factors and perceived value, diversity of digital music products and quality of digital music system affects significantly on the perceived value. but, usability of digital music service use does not have an effect on the perceived value. Second, as the result of analysis of the relationship between digital music service acceptance factors and customer satisfaction, diversity of digital music products, usability of digital music service and quality of digital music system affects significantly on the perceived value. These finding should assist digital music marketers and academics in their understanding of building loyalty on digital music service.

• The Journal of Fisheries Business Administration
• /
• v.48 no.2
• /
• pp.33-51
• /
• 2017

The purpose of this study is to estimate conservation value of fisheries resource protected area by the double-bounded dichotomous choice contingent valuation method. The data in this analysis come from a survey of respondents of resident in fisheries resource protected area using a proportional stratified sampling from the population. The questionnaires covered all the 5 fisheries resource protected area and the sample size of every protected area was 120 questionnaires. The survey period was from August to October in 2016. Above all, the average willingness to pay amount(WTP) per person of Namhae-Tongyoung I, Namhae-Tongyoung II, Jindong bay, Hansan bay, Cheonsu bay is estimated \6,215, \13,215, \6,405, \9,785, and \10,390 respectively. And, the total value of Namhae-Tongyoung I, Namhae-Tongyoung II, Jindong bay, Hansan bay, and Cheonsu bay is evaluated \108.8 billion, \357 billion, \118 billion, 210.2 billion, \ 245.8 billion respectively. Moreover, the yearly value of Namhae-Tongyoung I, Namhae-Tongyoung II, Jindong bay, Hansan bay, and Cheonsu bay is evaluated \6 billion, \19.6 billion, \6.5 billion, 11.6 billion, \ 13.5 billion. In conclusion, fisheries resource protected area has the higher conservational value. Consequently, it is essential for now or future generation's use of fisheries resources. In light of the fisheries resource protected area's value and importance, this should be promoted to the public including the local community who utilizes fisheries resource protected area wisely. Also, this suggests that the policy for fishery resource's creation and management is needed in fisheries resource protected area.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.8
• /
• pp.3-11
• /
• 2001

This paper describes an implementation of inverse filter using SVD in order to recover the input in multi-channel system. The matrix formulation in SISO system is extended to MIMO system. In time and frequency domain we investigates the inversion of minimum phase system and non-minimum phase system. To execute an effective inversion of non-minimum phase system, SVD is introduced. First of all we computes singular values of system matrix and then investigates the phase property of system. In case of overall system is non-minimum phase, system matrix has one (or more) very small singular value (s). The very small singular value (s) carries information about phase properties of system. Using this property, approximate inverse filter of overall system is founded. The numerical simulation shows potentials in use of the inverse filter.

• Journal of Korean Neurosurgical Society
• /
• v.60 no.2
• /
• pp.232-238
• /
• 2017

Objective : An apparent increase of use of drugs affecting hemostasis in our neurosurgical department since the 1990s has encouraged us to investigate whether these drugs influence the clinical course and results of surgery for chronic subdural hematoma (CSDH). Methods : This retrospective analysis included 178 patients admitted for CSDH from 2007 to 2011 who were divided into two groups : on drugs affecting hemostasis (40; 22%) and no bleeding disorders (138; 78%). Medications in the first group included oral anticoagulants (33; 82.5%), antiplatelets (5; 12.5%) and low molecular weight heparins (2; 5%). Results : The patients on drugs affecting hemostasis were older ($74.3{\pm}7.4$ vs. $68.4{\pm}14.8$; p-value 0.01) and the group without bleeding disorders had more head trauma history (61% vs. 38%, p-value 0.01). The groups did not differ in bilateral hematoma rates (25% vs. 20%, p-value=NS). At diagnosis, mean hematoma thickness was lower in patients on drugs affecting hemostasis ($18.7{\pm}7.4mm$ vs. $21.9{\pm}7.9mm$, p-value<0.01). Average stay of hospital was 1 day longer in patients on drugs affecting hemostasis ($11.7{\pm}4.1$ vs.$10.9{\pm}5.3$, p-value=NS) and was related to the necessity of bleeding disorder reversal. Mean neurological status at presentation was similar between the groups (p-value=NS) as was the likelihood of hematoma recurrence (p-value=NS). Glasgow Outcome Scale results were comparable. Conclusion : Patients on drugs affecting hemostasis are less often aware of a head trauma history, possibly suggesting a higher CSDH risk after minor trauma in this group. In these patients, smaller hematomas are symptomatic, probably due to faster hematoma formation. Drugs affecting hemostasis do not affect treatment results.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.10 no.5
• /
• pp.93-103
• /
• 2015

Residential environment is not only the physical aspects affected by the unique characteristics of the residents, social, economic, cultural, etc. are closely related to many environmental factors. This research is based on choice attribute theory that substantially explains how housing choice attributes affect loyalty via image, perceived value in Secho. This paper investigate empirically relationship between selection properties of residential environment and loyalty, moderating effect of image and perceived value. Results were computed using SPSS 20.0 statistical analysis programs. The results are summarized as follows. First, The elements of choice attribute are divided into six factor, such as regional reputation, green environment, convenience, property value, safety, housing status. In the results of the analyses, housing choice properties gives a positive influence to the loyalty. Second, testing its mediating role, I use the three regression equation models by Baron and Kenny. When the mediator effect of image, perceived value was represented, the effect of image and perceived value was statistically significant. Thus, the mediating role of image and perceived value was supported. It means the higher image and perceived value can enhance loyalty of Secho.

• Water for future
• /
• v.15 no.2
• /
• pp.23-32
• /
• 1982

This study is to clarify the relation between the maximum 24 hour rainfall and the daily rainfall of a designated time 10 A.M., using the 506 rainfall datum from 32 rain-guage stations on the Han river basin covering a period of 7 years and trying to estimate the ratio of two data in accordance with the amount of rainfall respectively. The Mononobe's formula, which is widely used in this country, has the value of 2/3 power in it. The "n" was considered instead of 2/3 and derivated for each guaging station. The results make it possible to establish the Ison-n value map, and show that the n value is affected mainly by the topographical conditions. The daily rainfall of a designated time can be modified by the results of this study and expressed as Y(%)=218.25/R$$. But in the case of exceeding 200mm/day, it is recommended to use the 110% for safety. On the problems of intensity-duration concerned with the planning of public works, the formula can be expressed as r$$=fRday/24.(24/t)$$, where "f" is Y(%) divided by 100. As this study was done with the datum within shor period, it is necessary to study more about the "n" and "f" value so as to get previse value in the future.o as to get previse value in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.37 no.12
• /
• pp.1232-1237
• /
• 2009

The ICAO and FAA are developing and verifying of GBAS for civil aircraft landing and take-off. The guarantee of aircraft integrity issue is the important part of GBAS. To guarantee integrity, the GBAS ground facility broadcasts various informations to aircraft. The informations are related to the estimated accuracy of each pseudorange correction and the estimated error terms, for example B-value and standard deviation of the ground facility error. These parameters are used to calculate position error (estimated value of the user). If estimated position errors don't satisfy requirements, aircraft use alternate navigation means. In this paper, GBAS reference stations's real data, which operated by KARI (Korea Aerospace Research Institute) in Jeju international airport, are used to development of new ground facility error standard deviation model. We verify improvement of GBAS availability, with respected to vertical protection level, using B-value based a new ground facility error standard deviation model and a sigma inflation factor.

• Korean Journal of Digital Imaging in Medicine
• /
• v.17 no.1
• /
• pp.33-41
• /
• 2015

This study attempts to examine the clinical usefulness of High b-value DWI (diffusion weighted imaging) for brain tumors with an edema. Subjects were seven patients selected from 65 patients who received an MRI scan for suspected encephalopathy and confirmed diagnosis at our hospital from February to July 2015 (male: 7, average age : 66 years old). As test equipment, 3.0T MR System (ACHIEVA Release, Philips, Best, The Netherlands) and 8Channel SENSE Head Coill were used. DWI checks on the use of the variable TR 5460ms, TE 132ms, Slice Thickness 4mm, gap 1mm, Slice number 29 is, 3D T1WI is TR 8.4ms, TE 3.9ms, matrix size $240{\times}240$, Slice can set 180 piecesIt was. b value of 0, 1,000, 2,000 s/mm2 with DWI acquisition and 3D T1WI enhancement five minutes after the Slice Thickness 3mm, gap 0mm to reconstruct the upper face axis (MPR TRA CE) was. As for the experiment, in b-value 1,000 and 2,000 images, SNR and the lesion at the lesion site and CNR in the normal site opposite to the lesion are measured. WW(window width) and WL(window level) are made equal in MRICro software, and the volume of the lesion is measured from each of b-value and MPR TRA CE image. Using SPSS ver. 1.8.0.0 Mann Whitney-test was analyzed for SNR and CNR, while Kruskal-Wallis test was analyzed for volume.