• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.30 no.6_1
• /
• pp.539-547
• /
• 2012

Volume survey for earthwork is conducted periodically at every month at large scaled construction sites for request payment for the construction. Currently, the earthwork volume is calculated on the overlapped drawing for two cross sections which were created by new and previous surveying data observed by GPS and TS. However the survey is required lots of time and expenses as it is a pin-point surveying method thus surveyors intend to get data only for the heavy undulated topographic features chosen by himself to save time and expenses. Consequently, it causes poor results due to low dense measurement as well as it's not matched with the results by another surveyors. As a result, the conflicts related in earthwork volume calculation often arises among the owner, contractors and sub contractors. In this study, we developed a method to get surveying data for fast and accurate volume calculation using 3D Mobile Laser System and conducted an application test. Also we carried out experiments for topographic survey using MLS to judge for the application additionally. The results showed that we could reduce a time for cross section survey from 48 hours to 2 hours and collected high dense data which have 0.2m interval instead of 3m interval compare with existing method. Also we could make a map which has high accuracy within 10cm in horizontal through topographic survey using MLS.

• Journal of the Korean Society of Radiology
• /
• v.5 no.4
• /
• pp.161-169
• /
• 2011

This research experimented on the change of the multiple colleague scan angle facing one scan object facet to many directions of the form of 3D about the visual angle nervous system forming the cubic distribution with the gradient magnetic field of the mri system and considered the existing basic angle oblique direction test coverage and comparison. MR system can freely select various pulse sequence and image slice. To oblique imaging for optic nerve viewing, we have studied the variation of scan angle between typical oblique scan method (sagittal-coronal plane) and multi directional angles oblique scan method (sagittal-coronal-axial plane) using gradient of MR system. In this study, the subjects of the experiment were normal adults in our country. As a result, we confirmed that multi directional angles oblique scan method can display anatomical information of more wider area than typical oblique scan method. In addition, to clearly display optic nerve, we also confirmed that image slice thickness and pulse sequence have effect on it.

• Journal of the Korean Geographical Society
• /
• v.32 no.4
• /
• pp.421-434
• /
• 1997

Flume experiments are conducted to describe channel adjustments at stream confluences and to examine some factors to which changes in channel characteristics are subject. There are different factors controlling channel size and shape; shereas the fomer is primarily controlled by water discharge alone, the latter including channel slope is influenced by sediment load as well as water discharge. The morphometric adjustments of confluent tributaries can be consequently classified into three types based upon changes in sediment concentration which are associated with the relative increasing rates of water discharge and sediment load at these sites. Flow is accelerated at stream confluences due to the convergence of confluent flows, causing an sharp increase in velocity. It restrains an increase in channel capacity, and furthers a decrease in channel slope, of a receiving stream. As a result, effects of slight increases in sediment concentration hardly appear on changes in channel characterisitics at stream confluences.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.2103-2107
• /
• 2009

우리나라는 계절별 강수량 변화가 크기 때문에 하천개발 및 관리에 어려움이 많을 뿐만 아니라 하천에 설치된 많은 취수보와 같은 하천횡단구조물로 인해서 하천 생태계가 악화되어 있다. 최근 들어 하천생태 복원을 위하여 자연형 하천 조성사업과 보에 어도설치가 활발하게 이루어지고 있다. 그러나 어류 소상에 효과적인 어도를 설치하기 위해서는 하천에 서식하는 다양한 어류에 대한 어류역학적인 특성이 필요하나 이에 대한 조사연구는 미흡한 실정이다. 특히 어류의 유영력이나 도약력은 어도의 설계의 완성도 및 어도시설 운영관리에서 대단히 중요한 요소이다. 따라서 본 연구에서는 우리나라 하천에 널리 서식하는 어류인 피라미를 대상으로 도약능력에 관하여 실험하였다. 어류의 도약능력은 낙차가 있는 흐름에서 어류가 상류로 이동하기 위한 중요한 이동수단이다. 어류의 도약에 영향을 미치는 어도 인자로는 격벽높이, 월류수심, 유속, 어도경사 및 유량을 들 수 있다. 피라미의 도약능력 실험은 폭 28cm, 길이 140cm인 개수로에서 격벽높이는 5${\sim}$10cm, 월류수심 1.2${\sim}$5cm, 낙차 약 4cm의 조건으로 이루어졌다. 실험유량은 약 0.378${\ell}$/s이고, 경사는 1:20${\sim}$1:15 이다. 도약능력은 소상율의 크기로 판단하였으며 피라미의 소상율은 격벽높이 10cm와 월류수심 3cm에서 유속 4.19cm/sec일 때를 정점으로 유속의 증가에 따라 급격히 감소하였다. 이는 어류의 생태적인 특성과 작은 유속이 어류이동 유인효과에 영향이 작기 때문인 것으로 판단된다. 또한 피라미의 체장이 클수록 소상율도 증가하는 관계를 나타내었다.

• Investigative Magnetic Resonance Imaging
• /
• v.1 no.1
• /
• pp.66-74
• /
• 1997

fMRI, functional MRI introduced receently appears based on the gradient echo technique which is sensitive to the field inhomogeneity developed due to the local susceptibility changes of blood oxygenation and deoxygenation. There has been many variants of the basic gradient echo sequence which is sensitive to the local inhomogeniety, among others such as GRASS or SSFP to EPISTAR are the most commonly used gradient echo techniques. Common to all these gradient echo techniques is that the signal due to the susceptibility effects is generally decreased with increasing inhomogeneity due to the $T2^{*}$ effect or conventionally konwn as blood oxygenation level dependent(BOLD) effect. It is, also found that the BOLD sensitivity is also dependent on the imaging modes, namely whether the imaging is in axial, or coronal or sagittal mode as well as the directions of the vessels against the main magnetic field. We have, therefore, launched a systematic study of imaging mode dependent signal change or BOLD sensitivity as well as the signal changes due tothe tilting angle of the imaging planes. Study has been made for both TRFGE sequence and CGE sequence to compare the distinctions of the each mode since each technique has different sensitivity againsst susceptibility effect. Method of computation and both the computer simulations and their corresponding experimental results are presented.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.1985-1990
• /
• 2008

1970년대 이후의 고도경제성장기에 치수대책과 동시에 건설골재로서 하상이 굴착된 하천이 많으며, 국가하천 지정구간외에서는 평균하상고가 1.0m 이상 저하한 하천구간도 많다. 또한 국가하천은 상류의 사방공사나 댐건설에 의한 영향이 복합적으로 하도에 나타나고 있어 하상굴착이 하도특성에 어떤 영향을 미치는가를 실증적(實證的)으로 검증하는 것은 어려운 과제이다. 하천에서의 골재채취는 제방부의 침식에 의한 호안파괴, 하상저하에 따른 교량이나 취수보 등 구조물의 기초 노출이 치수적인 문제를 야기할 뿐만 아니라, 단시간내에 하도의 지형구조를 급격하게 변화시켜 여울 소의 하상구조 교란이나 수중 및 하천변의 서식처 파괴 등으로 하천의 물리적 환경에 큰 영향을 미침으로써 생태계를 교란하거나 파괴하는 결과를 초래하게 된다. 본 연구에서는 골재채취로 인하여 교란된 하천의 복원 및 적응관리 계획수립의 전단계에 필요한 교란평가기법을 개발하기 위하여 황강, 남강 및 감천을 대상으로 하여 대조구간과 교란구간을 선정하고 조사 분석하였다. 하천골재 채취가 없거나 경미한 대조구간에서는 홍수량이 변하지 않으면 terrace 모양의 하안부 재료가 하상재료와 거의 같기 때문에 홍수가 있으면 침식된 원래의 하폭으로 회복되는 방향으로 변하지는 않는 경향이 나타났다. 반면에 골재채취가 많은 경우 큰 홍수시의 저수로부의 수심을 증가시키기 때문에 수충부 등의 최심하상고가 크게 되는 경향이 있었으며, 고수부는 침수되는 빈도와 수심이 감소하기 때문에 토사의 퇴적속도(고수부의 상승속도)의 감소, 퇴적물의 세립화 경향이 나타나서 모래, 실트가 퇴적하지 않는 고수부상에 모래, 실트가 퇴적되는 경우가 있고, 반대로 고수부의 퇴적속도가 상승하는 경우도 있었다. 골재채취로 횡단방향의 평탄화가 초래되어 여울 소의 하상구조가 교란됨과 동시에 구간별로 종단경사가 완만해지며, 대부분 교량부에 하상유지공을 설치해야 할 정도로 하상경사가 급변하는 구간이 다수 조사되었다. 또한 선행연구에서 개발된 하상서식환경, 하상재료, 유속/수심상황, 유사퇴적, 하도흐름상태, 하도개수, 여울출현 빈도, 하안 안정성, 식생피복 및 하반림 등 10개의 교란평가항목을 적용하여 대조구간과 비교 평가하였다.

• PNF and Movement
• /
• v.15 no.3
• /
• pp.253-257
• /
• 2017

Purpose: This study was conducted to predict the risks that arise while standing on mediolateral ramps at various ramp angles by identifying the ratio of medial to lateral gastrocnemius muscle activities. Methods: The subjects were 20 healthy adult men. Seven mediolateral ramp angles ($0^{\circ}$, $2^{\circ}$, $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$, and $25^{\circ}$) were applied for the experiment. The ratio of medial to lateral gastrocnemius muscle activities in each condition was measured using electromyography, and the measured data were converted to root mean square values to calculate the activity ratios. Results: The study results showed statistically significant differences in the ratio of mediolateral gastrocnemius muscle activities according to the selected mediolateral ramp angles. The results of a post hoc test confirmed that the multifidus muscles were asymmetrically used on the two sides at mediolateral ramp angles of $5^{\circ}$ or higher. Conclusion: This study found that an asymmetric use of the multifidus muscles began at a mediolateral ramp angle of $5^{\circ}$, and the provision of propulsion using the ankle joints on mediolateral ramps at $5^{\circ}$ or steeper was maneuvered differently from that on flat ground. This suggests that individuals with balance control disorder have the risk of falling due to ankle sprains and unstable balance control. Therefore, patients and elderly people are required to exercise caution when crossing $5^{\circ}$ or steeper ramps.

• Journal of Korean Society for Geospatial Information Science
• /
• v.21 no.3
• /
• pp.3-9
• /
• 2013

As interest in green growth picks up, the importance of bicycles which are an environment friendly means of communication has been magnified. However, bicycle routes which are the base of bicycles are designed without considering topographic elements and thus many users are experiencing inconvenience in using bicycles. The present study presents a routing technique to select optimal routes when selecting routes in commuting to school utilizing bicycles. To this end, a formula for optimum route calculation considering slope and intersections was drawn and a method to select optimum routes by applying modified Dijkstra Algorithms was studied. According to the results, the bicycle routes for commuting to school should be selected by the shortest time rather than the shortest distances to the destination, because it required reach the destination faster. Therefore when selecting the routes, it must be based on the shortest time considering waiting time due to crosswalks or crossroads and speed variations due to slopes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.4
• /
• pp.367-374
• /
• 2002

Maintainability of highways is an important problem that is considered in the planning steps of a highway development process. A number of asset management systems have been developed to precisely predict maintenance and pavement expenditures for better decision making, But these systems are not helpful in reducing maintenance costs. Optimization of some highway design characteristics in the planning phases may reduce maintenance costs over the life cycle of highway. The formulations for initial and maintenance costs have been developed based on which design variables can be chosen to minimize these costs, focusing on the sideslope in cut and fill sections. Maintenance cost has been represented as a function of sideslope, width of highway cross section, and annual average daily traffic. A real geographic database of between Chung joo and Sang joo city in Choong buk was used and it is presented to investigate the sensitivities of maintenance cost and soil characteristics in selecting alignments. In this study, we present that maintenance cost and soil characteristics are important considerations in alignment optimization.

• Journal of Korea Water Resources Association
• /
• v.49 no.12
• /
• pp.961-969
• /
• 2016

Due to the recent requirement of installing low-head structures considering environmental aspects, various types of fixed weir have been suggested. However, the design guideline of transverse structures for practical application is very limited. The purpose of the present study is to analyze the hydraulic properties of the fixed weirs installed at the small and middle sized rivers of Korea depending on the physical specifications to provide fundamental data that may be reflected to the design of a low-head fixed weir considering the relevant environmental aspects. The basic discharge coefficient of slope-type and step-type weirs depending on change of crest was estimated, and a stage-discharge curve was developed. In addition, the flow properties under free flow and submerged flow conditions were analyzed by varying the hydraulic conditions such as discharge and crest.