• 한국수자원학회논문집
• /
• 제42권12호
• /
• pp.1113-1124
• /
• 2009

구하도 및 폐천복원은 하천에서의 이수와 치수적인 기능뿐만 아니라 환경 및 생태 서식처 기능을 강화하고 개선하기 위한 여러 방법들 중 하나이며 이러한 구하도를 복원하기 위해서는 주수로와의 하도 안정성을 고려하여 횡단면 형태를 결정하고 하도선형을 설계하게 된다. 이러한 하도설계시 기준이 되는 유량이 반드시 필요하며 이 기준유량을 하도형성유량 또는 지배유량이라고 한다. 일반적으로 하도형성유량을 산정하는 방법으로는 만제유량, 특정 재현기간별 유량, 유효유량을 계산하여 결정하는 방법이 있다. 본 연구에서는 구하도 복원 사업이 시행되는 청미천 구간에 대해 만제유량, 특정 재현기간별 유량, 유효유량을 산정하여 상호 관계를 분석하고 과거의 하상변동 특성 자료와 비교하여 연관성을 평가하였다. 청미천 구하도 복원구간의 만제유량은 HEC-RAS 자료를 이용하여 만제수위에 해당되는 유량으로 산정하였으며 488 $m^3/s$인 것으로 나타났고 이는 1.5년과 2년 빈도 사이의 유량에 포함되는 것으로 나타났다. 또한 유사량 자료와 과거 일유량 자료를 이용하여 계산된 유효유량은 만제유량보다 큰 값을 갖는 것으로 나타났다. 과거 측량자료 분석에 의하면 청미천의 대상구간 하도는 1994년에 비해 2008년 현재 하도가 침식된 것으로 나타났으며 이는 유효유량을 소통시킬 수 있는 형태로 하도가 진화하고 있다는 것을 의미하며 곧 하천이 안정한 상태로 변화하고 있다는 것을 의미한다.

• 한국관개배수논문집
• /
• 제21권1호
• /
• pp.118-126
• /
• 2014

In this study, the use of the spur of riverbank technique is being investigated. The spur of the riverbank typically reduces the velocity of flow and protects the embankments by increasing friction along the water and the banks. This also has an effect in the rise of water level upstream. It is also used for the rectification of riverside line and restoration of the waterway through sedimentation near the spur of the riverbank. In this study, physical-scaled experiments are conducted to investigate the process of creating a mild meandering channel using the spur of the riverbank with varying water flows and sedimentation functions. The hydraulics observations are taken with respect to the varying heights and length of the riverbank's spurs and the distance between each spur for the formation of the mild meandering channel. It is observed that for 1.06 times of the meander length, it requires 2 times of the interval with each spur of river width. Similarly, 1.25L times of the meander length, it requires 0.5 times of the interval with each spur of river width. The sand accumulation is induced by the spur of riverbank when the spur of riverbank's heights are more than 40% of water depth and the length of the spur of riverbank needs under than 20% of river width for avoid exaggerated sand accumulation in the center of channel.

• Archives of Plastic Surgery
• /
• 제39권5호
• /
• pp.518-521
• /
• 2012

Background Skin cancer is the most common malignant tumor in humans. Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the two most common types of skin cancers. When skin cancer is clinically suspected, preoperative biopsies are recommended for a definite diagnosis. However, despite a concern over potential increased risk of metastasis associated with mechanical manipulation, there have been few investigations into whether a preoperative biopsy affected the recurrence of BCC and SCC. Methods Primary BCC or SCC patients who underwent standard surgical excision from 1991 to 2010 were reviewed and a retrospective analysis was performed. Ultimately, 45 BCC patients and 54 SCC patients, who did not meet the exclusion criteria, were analyzed. To identify whether a preoperative biopsy affected the recurrence of BCC and SCC, the recurrence rates of each with and without biopsy were compared. Results Preoperative biopsy had no statistically significant effect on recurrence (BCC, P=0.8680; SCC, P=0.7520). Also, there was no statistical significance between the interval from initial biopsy to first operation and recurrence (BCC, P=0.2329; SCC, P=0.7140). Even though there was no statistical significance, the mean interval from the biopsy to the operation among the BCC patients who underwent preoperative biopsy was 9.2 months in those who had recurrence and 2.0 months in those who had no recurrence. Conclusions There was no statistically significant relationship between preoperative biopsy and recurrence of BCC and SCC. However, there was a tendency toward recurrence in patients with a longer interval between the biopsy and the corrective operation in BCC.

• Ocean and Polar Research
• /
• 제33권1호
• /
• pp.77-83
• /
• 2011

In this study we examined the economic value of restoration technology for oil spill using contingent value methods. One and one half approach to questionnaires can be taken when analyzing tax payer situations as well as single bound approach. The results of the empirical analysis suggest three conclusions. First, the economic value of the restoration technology considered are estimated to be between 8,439 won to 11,867 won per month. Second, the WTP is estimated differently depending on the approaches, OOHB and SB, and the degrees of difference are very sensitive to the model specifications. This empirical result supports the argument for using interval for the economic value when using CVM. Third, the empirical results may provide useful input to policy authorities attempting to estimate the economic justification of the R&D investment for developing an ocean environmental restoration technology.

• 대한토목학회논문집
• /
• 제31권4B호
• /
• pp.361-367
• /
• 2011

하천 정비 및 하천 복업사업의 기준유량이 되는 하도형성유량 산정은 안정하도 설계시 반드시 선행되어야 하는 것이다. 국내의 경우 하도형성유량 산정방법에 대한 연구가 많이 수행되지 않아 특정패턴을 도출하기가 어려운 실정이다. 국내하천의 경우 외국의 주요하천과 비교하여 하상계수가 크게 나타나는 특성으로 인해 외국사례를 국내에 적용하기에 어려움이 있다. 따라서 현재 구하도 복원이 진행 되고 있거나 계획되어 있는 만경강, 청미천, 함평천을 대상으로 하도형성유량 산정을 위해 만제유량, 특정 재현기간별 유량, 유효유량을 산정해보고 각각의 상호관계를 분석하여 하상계수가 큰 국내하천에 적용 가능한 하도형성유량을 제안하고자 한다. 만제유량은 대상유역의 지형자료를 이용한 HEC-RAS 모의를 통해 산정하였으며 특정 재현기간별 유량과 유효유량은 대상구간의 유량, 하상토, 유사 자료를 이용하여 산정하였다. 산정결과 하상계수가 큰 하천에서는 유효유량이 만제유량보다 크게 나타났으며 하상계수와 관련하여 특정 재현기간별 유량은 일관성 있는 특징이 없는 것으로 나타났다.

• 구강회복응용과학지
• /
• 제19권4호
• /
• pp.309-315
• /
• 2003

When the exposure surface of restoration is brushed with various toothpaste in the mouth, wear or undesirable surface deposit of restoration can occur. Surface change of gallium alloys according to brushing and toothpaste may directly affect oral hygiene. The aim of this study was to evaluate the surface alterations of Gallium alloys during tooth brushing with different prophylactic agents. Two gallium-alloys and an amalgam as a control were investigated. Without and with brushing were applied with three kinds of prophylactic agents on the sample for 0, 1, 5, 10, 60 and 360 minutes. At each time interval, surface roughness was recorded by a profilometer and some pictures were taken by a SEM. All results were analyzed by the one-way ANOVA, followed by Tukey multiple comparisons and the simple linear regression analysis. The results indicate that gallium alloys are more susceptible to surface degradation during tooth brushing than amalgam with respect to the specific prophylactic agent used.

• 한국환경생태학회지
• /
• 제29권2호
• /
• pp.292-303
• /
• 2015

The objective of this study is to evaluate the spatial restoration of Hampyeong Stream and to analyze the determinants of demand for the multi-functionalities of the stream. A Contingent Valuation Method (CVM) was used to estimate the multi-functional public benefits of restored stream area, and major determinants were scrutinized by establishing a demand model. The research data was collected by conducting a survey intended for Hampyeong's local residents, resulting in 284 valid samples. In terms of determinants that affect willingness to pay (WTP), 'physical factor of waterfront area' and 'experience factor of stream space' showed a significantly positive influence on WTP. As a result of applying a double-bounded CVM, the willingness to pay for the restored Hampyeong Stream area indicated a potential contribution of 22,523 won (17,362~27,459 won, 95% confidence interval). When multiplying the number of households in Hampyeong-gun, the total annual value of Hampyeong Stream spatial restoration is approximately 302million won.

• 한국산림과학회지
• /
• 제97권5호
• /
• pp.540-546
• /
• 2008

Enrichment planting has been used as one of the promising restoration techniques to accelerate the natural restoration process of secondary forests or logged-over forests in Myanmar, The objectives of this study were to examine the growth performances of two commercial species such as Teak (Tectona grandis Linn f.) and Padauk (Pterocarpus macrocarpus Kurz) in response to different canopy opening treatments and to examine the suitability of these species in enrichment planting activities for the restoration of degraded tropical forests in Myanmar. In this study, split plot design was applied, and three levels of canopy openings were experimented. The survival rate and height growth of two species were measured four times with 6 month interval. The root collar diameter (RCD) was also measured in the last assessment. Although the survival rate of seedlings was not significantly different among the three treatments (p>0.05) as well as between two species (p>0.05) for all consecutive measurements, height (p<0.05) and RCD were significantly different (p<0.001) among the treatments, T. grandis seedlings thrived best under complete canopy opening (i.e., 5 m width canopy opening with strip-clear cutting) while P. macrocarpus seedlings under partial canopy opening (without felling of marketable tree species). Because this study is concerned with only for young stage of seedlings, continuous assessment and follow-up tending activities are needed to verify the species suitability and optimum width of canopy opening for enrichment planting activities in restoration of degraded forests of Myanmar.

• 한국군사과학기술학회지
• /
• 제8권3호
• /
• pp.73-82
• /
• 2005

This paper describes shock waveform synthesis methods for a shock response spectnlm over a short time interval with which intereference between parts within a test item is increased to perform a sufficient shock test for damage or malfunction which may be caused by the interference between parts, and a digital filter for obtaining a shock response history required for the shock waveform synthesis and a digital inverse filter for restoration by inversely using the digital filter. The time at which the maximax value occurs in the response history is detected in order to establish a delay time which is one of the parameters in the wavelet, on the condition that the natural frequency of SDOF system with a Q (quality factor) of 10 equals to the wavelet frequency of the zero delay wavelet input. A shock response spectrum over a short time interval and an abrupt change in the acceleration for an instant are illustrated as features of the synthesized waveform.

• Journal of Korean Neurosurgical Society
• /
• 제42권5호
• /
• pp.371-376
• /
• 2007

Objective : Balloon kyphoplasty can effectively relieve the symptomatic pain and correct the segmental deformity of osteoporotic vertebral compression fractures. While many articles have reported on the effectiveness of the procedure, there has not been any research on the factors affecting the deformity correction. Here, we evaluated both the relationship between postoperative pain relief and restoration of the vertebral height, and segmental kyphosis, as well as the various factors affecting segmental deformity correction after balloon kyphoplasty. Methods : Between January 2004 and December 2006, 137 patients (158 vertebral levels) underwent balloon kyphoplasty. We analyzed various factors such as the age and sex of the patient, preoperative compression ratio, kyphotic angle of compressed segment, injected PMMA volume, configuration of compression, preoperative bone mineral density (BMD) score, time interval between onset of symptom and the procedure, visual analogue scale (VAS) score for pain rating and surgery-related complications. Results : The mean postoperative VAS score improvement was $4.93{\pm}0.17$. The mean postoperative height restoration rate was $17.8{\pm}1.57%$ and the kyphotic angle reduction was $1.94{\pm}0.38^{\circ}$. However, there were no significant statistical correlations among VAS score improvement, height restoration rate, and kyphotic angle reduction. Among the various factors, the configuration of the compressed vertebral body (p=0.002) was related to the height restoration rate and the direction of the compression (p=0.006) was related with the kyphotic angle reduction. The preoperative compression ratio (p=0.023, p=0.006) and injected PMMA volume (p<0.001, p=0.035) affected both the height restoration and kyphotic angle reduction. Only the preoperative compression ratio was found to be as an independent affecting factor (95% CI : 1.064-5.068). Conclusion : The two major benefits of balloon kyphoplasty are immediate pain relief and local deformity correction, but segmental deformity correction achieved by balloon kyphoplasty does not result in additional pain relief. Among the factors that were shown to affect the segmental deformity correction, configuration of the compressed vertebral body, direction of the most compressed area, and preoperative compression ratio were not modifiable. However, careful preoperative consideration about the modifiable factor, the PMMA volume to inject, may contribute to the dynamic correction of the segmental deformity.