• Journal of Korean Tunnelling and Underground Space Association
• /
• 제10권1호
• /
• pp.69-79
• /
• 2008

Prediction of ground condition ahead of tunnel face might be the most important factor to prevent collapse during tunnel excavation. In this study, a non-destructive method to evaluate the phase velocity in model rock mass using wavelet transform of surface wave was proposed aiming at ground condition assessment ahead of tunnel face. Model tests using gypsum as a rocklike material composed of two layers were performed. A Piezoelectric actuator with frequencies ranging from 150 Hz to 5 kHz was selected as a harmonic source. The acceleration history was measured with two accelerometers. Wavelet transform analysis was used to obtain the dispersion curves from the measured data. The experimental results showed that the near-field effects can be neglected if the distance between two receivers is chosen to be three times the wavelength. A simple inversion method using weighted factor based on the normal distribution was proposed. The inversion results showed that the predicted phase velocity agreed reasonably well with the measured one when the wavelength influence factor was 0.2. The depth of propagation of surface wave was from 0.42 to 0.63 times the wavelength. The range of wavelength varying with phase velocity in dispersion curve matched well with that estimated by inversion technique.

• Journal of Veterinary Clinics
• /
• 제22권4호
• /
• pp.450-452
• /
• 2005

A 3-year-old, 43kg, pregnant Great Pyrenese was examined for clinical signs of acute weakness and anorexia for 4 days. The dog was in lateral recumbency at referral. The rectal temperature was within reference range, and the respiratory and heart rates were 36 breaths/min and 58 beats/min, respectively. The abdomen was distended, and several puppies were palpated. The mean fetal head diameter was 2.8cm in the ultrasonographic examination. The initial complete blood count and serum biochemical examinations revealed mild dehydration, mud hyperglycemia, hypochloremia, hyperkalemia, hyponatremia, and low sodium-potassium ratio. Serum BUN and total cholesterol values were slightly high. Hypoadrenocortical crisis was suspected on the basis of signs of acute collapse, hyponatremia and hyperkalemia. Adrenal gland function was evaluated by an ACTH stimulation test. The baseline cortisol concentration was $18.6{\mu}g/dl$ and the concentration at 1 hour after administration of tetracosactrin (ACTH, Synacthen) was $8{\mu}g/dl$. The dog was treated for the correction of assumed hypoadrenocortical crisis and substantial hyperkalemia. In addition to rapid infusion with saline solution, other medications administered intravenously included sodium bicarbonate and cimetidine hydrochloride. The dog was monitored with repeated serum electrolyte examination. After clinical stabilization, cesarean section was performed. All of 13 puppies were delivered, and the dog recovered from anesthesia without complications. The values of postpartum blood tests returned to normal or within reference range. The dog remained healthily.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• 제35권5호
• /
• pp.1025-1037
• /
• 2015

Flexible base isolation bearings that separate superstructure from ground have been widely used in the construction field because they make a significant contribution to increasing the fundamental period of the structure, thereby decreasing response acceleration transmitted into the superstructure. However, the established bearing devices installed to uphold the whole building give rise to some problems involved with failure and collapse due to lack of the capacity as modern structures are getting more massive and higher. Therefore, this study suggests new isolation bearings assembled with additional restrainers enabled to reinforcing and recentering, and then evaluates their performance to withstand the seismic load. The superelastic shape memory alloy (SMA) bars are installed into the conventional lead-rubber bearing (LRB) devices in order to provide recentering forces. These new systems are modeled as component spring models for the purpose of conducting nonlinear dynamic analyses with near fault ground motion data. The LRB devices with steel bars are also designed and analyzed to compare their responses with those of new systems. After numerical analyses, ultimate strength, maximum displacement, permanent deformation, and recentering ratio are compared to each model with an aim to investigate which base isolation models are superior. It can be shown that LRB models with superelastic SMA bars are superior to other models compared to each other in terms of seismic resistance and recentering effect.

• The Journal of Engineering Geology
• /
• 제22권2호
• /
• pp.223-231
• /
• 2012

Many cut slopes are located near national highways, resulting in large annual damage to infrastructure from the collapse of cut slopes. Therefore, to effectively maintain cut slopes, high-risk slopes should be identified and monitored. In this paper, we evaluate the effectiveness of the management of cut slopes using the risk score calculated from cut-slope inventory data. The inventory survey, as a simple assessment of the characteristics of various slopes, was performed to collect basic data that could be obtained visually in the field for the management of cut slopes. This method is not a precise survey, and it was composed of the general status and characteristics of cut slopes, the inspector's assessment, and inventory data in order to estimate a risk score for each slope. In this paper, we calculated the risk score by investigating the present status of cut slopes adjacent to 10,461 national roads. In order to evaluate the effectiveness of using risk score data, we compared the score for stable slopes with those of failed cut slopes. Failed cut slopes occurred in sections with the highest risk score. The results show that risk score derived from the inventory survey of cut slopes are useful in the management of cut slopes with risk of failure and in monitoring large numbers of cut slopes.

• International Commerce and Information Review
• /
• 제15권4호
• /
• pp.341-366
• /
• 2013

The term, Mittelstand, has no exact english translation for the definition, but, today, Mittelstand refers to small and medium-sized enterprises(SME), mostly family-owned firms in Germany. The Mittelstand is called the backbone of the German economy because it drove the economic miracle after World War II. During the global recession and the euro zone's debt crisis in recent years, in which european businesses have faced the near-collapse of competitiveness particularly in manufacturing, the German exports are booming and exceeded exports of China in 2012. Most importantly, the Germany economic performance has been widely attributed to the strength of the Mittelstand. Many of countries, even some leading public companies are seeking to emulate the success of the Mittelstand. Investors evaluate that many of Germany's investable "hidden champions" are Mittelstand companies. The purpose of this study is to present some of answers to the following questions: Firstly, what makes the German Mittelstand so successful? Secondly, what does the success of the German Mittelstand mean for the Korean SMEs in global competitiveness? Thirdly, what Korean government has to do improve the global competitiveness of the Korean SMEs? Some discussions in this study mention the managerial implications for Korean exporting SMEs particularly in manufacturing. Several factors that account for the success of the German Mittelstand are technological excellence and the tradition of family-owned management, concentration on niche market and globalization, and institutional supports. There are some of important lessons to be learned from the German Mittelstand. If the purposes of Korean SMEs want to remain in the sustainable competitive advantage and withstand unforeseen economic turbulences in the future, they must be able to meet the followings: 1) Technology that meets the global standard or exceeding it 2) Competitiveness in price in the global market 3) Active involvement in the globalization process, utilizing various entry modes Innovative products at globally competitive price are a crucial point for Korean exporting SMEs to achieve their competitive edge over others in the target markets abroad. It is time for Korean SMEs to cultivate a core competence in manufacturing in order to position Korea as a global manufacturing hub with SMEs leading.

• Journal of the Korean Society of Marine Environment & Safety
• /
• 제29권7호
• /
• pp.950-957
• /
• 2023

For safe mooring and towing between the ship and port, the equipment must be designed in accordance with the relevant international regulations. However, some small shipyards and engineering companies often do not fully comprehend the core contents. Therefore, the international regulations regarding towing and mooring equipment are reviewed and the bollard and chock are newly developed based on the Mooring Equipment Guideline 4 (MEG4) standards. A bollard is a mooring equipment used to fix a mooring rope to the hull. It has two columns and is mostly used in a figure eight pattern knots under the mooring condition. The chock, which is used to change the mooring rope direction coming into the ship from outside, is manufactured using a casting with curvature. The two mooring equipment are widely used in the stern, bow, and mid-side. Owing to the increase in the size of container vessels and LNG ships, the mooring rope load has increased and the safe working load of the mooring equipment must be revised. This study summarizes and examines the results of the allowable stress method obtained using finite element analysis modelling. To consider the mesh size effect, a reasonable criteria was suggested by referring the existing class guidance. Additionally, the safe working load was verified through nonlinear collapse analysis, and the elastic region against load increments was confirmed. Furthermore, the proposed evaluation method can be used to develop similar equipment in the near future.

• Journal of Korean Tunnelling and Underground Space Association
• /
• 제25권6호
• /
• pp.469-478
• /
• 2023

The deep tunnel in urban area is a future-oriented construction plan that allows the above-ground space to be used as an eco-friendly park and transportation infrastructure to be constructed in the underground space. However, tunnel construction is often depicted as to cause ground collapse in some media and movies. In fact, while the construction of a deep tunnel in the urban area is underway, the project face with difficulties due to opposition complaints from residents near the route. In this study, we sought to identify perceptions on deep space development and citizen concerns through a public opinion survey regarding deep tunnels. By analyzing laws relevant with the promotion of deep tunnel construction, we reviewed the possibility of public engagement at each stage of the construction and investigated separated surface rights related to compensation for underground space. Through the results of the public opinion survey, it was identified that the concerns of citizens were problems that current technology could solve. Citizen's concerns were improved into a system that confirmed the stability of tunnel construction through public participation, and improvement measures were presented to encourage cooperation from those concerned regarding the establishment of divided superficies.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• 제7권1호
• /
• pp.15-27
• /
• 1974

Since the summer of the year 1972 ulcer disease of common carp, colour carp ana goldfish had suddenly spread widely and caused a serious mortality at fish farms especially around Gim-hae and Yang-san, near Busan. The present study aimed to find out the causative organisms, histopathological changes and the way of treatment, and the results are summarized as follows : Two kinds of pathogenic bacteria, i. e, Chondrococcus columnaris and Aeromonas sp. were isolated from the mucus of the lesion. According to the macroscopic findings, these symptoms began with the hemorrhagic spots under scales which fell out, after the collapse of the dermis, which was followed by lesion to form ulcer, and then the muscle was exposed. The fin was eroded mostly from the distal part, but sometimes from the basal part. Gills showed grey colour, and this part of the tissue collapsed. According to the histopathological findings, the dermis was exposed after the collapsed of the epithelium of the skin, and the necrosis of the musculature occurred, the muscular fibre being destroyed. The epithelial cells of gill tissue proliferated, thus gill filaments were conglutinated and collapsed. Fatty degeneration happened at the liver but the other organs seem to be normal. Treatment with the following mixtures were effective the water temperature of $22\~25^{\circ}C$, but not effective when the temperature was under as low as $13\~15^{\circ}C$. Mixture 1. Aivet (HB-115.HCI) 0.3ppm Malachite green 0.2ppm. Dipterex 0.4ppm Mixture 2. Furanace (P-7138) 0.05ppm Malachite green 0.2ppm Dipterex 0.4ppm When lesion healed, the epithelium, dermis, and the muscular fibre were regenerated.

• Korean Journal of Remote Sensing
• /
• 제34권6_4호
• /
• pp.1479-1488
• /
• 2018

On September 3rd 2017, strong artificial seismic signals from North Korea were detected in KMA (Korea Meteorological Administration) seismic network. The location of the epicenter was estimated to be Punggye-ri nuclear test site and it was the most powerful to date. The event was not studied well due to accessibility and geodetic measurements. Therefore, we used remote sensing data to analyze surface changes around Mt. Mantap area. First of all, we tried to detect surface deformation using InSAR method with Advanced Land Observation Satellite-2 (ALOS-2). Even though ALOS-2 data used L-band long wavelength, it was not working well for this particular case because of decorrelation on interferogram. The main reason would be large deformation near the Mt. Mantap area. To overcome this limitation of decorrelation, we applied offset tracking method to measure deformation. However, this method is affected by window kernel size. So we applied various window sizes from 32 to 224 in 16 steps. We could retrieve 2D surface deformation of about 3 m in maximum in the west side of Mt. Mantap. Second, we used Pleiadas-A/B high resolution satellite optical images which were acquired before and after the 6th nuclear test. We detected widespread surface damage around the top of Mt. Mantap such as landslide and suspected collapse area. This phenomenon may be caused by a very strong underground nuclear explosion test. High-resolution satellite images could be used to analyze non-accessible area.