• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.73-80
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• 2008

ALINEA algorithm, which is one of the best on-ramp metering algorithms, was designed to control the traffic volume from on-ramp in order to maintain the optimal occupancy rate of the detectors installed downstream of the merge area. But, the reliability of occupancy rate estimated from the loop detectors, which are used most commonly in Korea, is relatively lower than other parameters such as speed and volume. Moreover, because occupancy rate depends on the length of loop detectors and site, lots of calibration work is required whenever they are installed in order to estimate the occupancy rate. Therefore, there exists room for improvement of ALINEA algorithm because only occupancy rate having some problems is considered as a control parameter in ALINEA algorithm. Practically it is difficult to measure or perceive the occupancy rate for traffic engineers and drivers. On the other hand, speed can be good alternative which can overcome the defect induced by using occupancy. In this study, occupancy based ALINEA algorithm is converted to speed based ALINEA assuming the linear relationship between density and speed.

• Membrane Journal
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• v.15 no.2
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• pp.105-113
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• 2005

Silica membranes were prepared on a porous metal sheet by ultrasonic spray pyrolysis method for gas separation at high temperatures. In order to improve the permselectivity, silica was deposited in the sol-gel derived $silica/\gamma-alumina$ intermediate layer by pyrolysis of tetraethyl orthosilicate (TEOS) at 873 K. The pyrolysis with forced cross flow through the porous wall of the support was very effective in plugging mesopores, Knudsen diffusion regime, that were left unplugged in the membranes. At permeation temperature of 523 K, the silica/alumina composite membrane showed $H_2/N_2$ and water/methanol selectivity as high as 17 and 16, respectively, by molecular sieve effect.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.1
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• pp.33-40
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• 1992

Several etching phenomena were observed and analyzed in diaphragm process performed on 4-inch (100) Si wafers for sensor application. In case of deep etching to above 300$\mu$m depth, the etch-defects appeared at etched surface could be classified into three categories such as hillocks, reaction products, and white residues. It was known that the hillock had a pyramidal shape or trapizoidal hexahedron structure depending on the density and size of the reaction products. The IR spectra showed that the white residue, which was due to the local over-saturation of Si dissolved in solution, was mostly Si-N-O compounds mixed with a small amount of H and C etc. Also, the difference in both the existence of etch-defects and etch rate distribution over a whole wafer was investigated when the etched surfaces were downward, upward horizontally and erective in etching solutions. The obtained data were analyzed through flow pattern in the etching bath. As the results, the downward and erective postures were favorable in the etch rate uniformity and the etch-defect removal, respectively.

• The Journal of the Acoustical Society of Korea
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• v.20 no.3
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• pp.76-82
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• 2001

Most fluid machines can be considered as periodic noise sources when operated under constant conditions, which allows for a frequency domain representation of the source and the associated acoustic field In the duct. In such a representation, the source is characterized by frequency-dependent values of both strength and impedance. Although knowledge of these values can be gained by either experimentation or by modeling, one-port acoustic characteristics of an in-duct source with high flow velocity, high temperature, and high sound level can be measured only by the multiload method using an overdetermined set of open pipes with different lengths as applied loads. However, the problem is that negative source resistances have been often measured. This paper reviews the possible causes of the problem, with reference to experimental and theoretical results, in an attempt to clarify the issue. A new interpretation is given for the violation of basic assumptions and the defect in the algorithm of multiload method. The major cause and mechanism of the problem is due to the violation of time invariance assumption of the source and the load impedance can seriously affect the final measured result of source impedance.

• Archives of Reconstructive Microsurgery
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• v.20 no.1
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• pp.51-56
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• 2011

During below knee amputation, the amputation stump must be covered with well-vascularized and sensate soft tissue. Many flaps can be used for this purpose, but available reconstructive options are limited. We performed reverse flow ALT flap elevation on two patients with below knee amputations to reconstruct defects in the stumps. The sizes of the defects in the stumps were $4{\times}16$ cm and $5{\times}5$ cm, respectively. The most distal portion of the defects were located 20 cm and 16 cm lateral to the knee joint in a curve, respectively. The size of the elevated flap was $5{\times}18$ cm for case 1 and $18{\times}10$ cm for case 2. The respective pivot points of the pedicles were 7 cm and 6 cm above the patella and the respective lengths of the pedicles were 17 cm and 16 cm. In both cases, venous congestion occurred on the second postoperative day and the flap distal to 10 cm or more from below the knee joint was necrotized at the second postoperative week. Surgeons should be cautious when using a reverse ALT flap to reconstruct a soft tissue defect located 10 cm or more distal from below the knee joint. Since a pedicle longer than 15 cm may develop partial necrosis of the flap, simultaneous application of antegrade venous drainage is recommended.

• Archives of Reconstructive Microsurgery
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• v.11 no.2
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• pp.141-145
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• 2002

Rectus abdominis muscle free flap is widely used for breast reconstruction and soft tissue defect in lower leg but donor-site morbidities such as abdominal wall weakness, hernia, bulging are troublesome. Recently, to minimize donor-site morbidity, there has been a surge in interest in deep inferior epigastric perforator(DIEP) free flap preserving the anatomy of rectus abdominis muscle, fascia, and motor nerve. Between August of 1995 and September of 2002, topographic investigation of DIEP was performed during the elevation of 97 cases of TRAM free flap and 5 cases of DIEP free flap. There were 84 cases of breast reconstructions, 12 cases of lower leg reconstructions, and 6 cases of head and neck reconstruction. We could observe total 10 to 12 perforators on each rectus abdominis muscle below umbilicus. Among these, the numbers of large perforators(>1.5mm of diameter) were mean 2.1 in lateral half of rectus abdominis muscle, mean 1.2 in medial half, and mean 0.5 in linea alba and paramedian. DIEP free flap provides ample amount of well vascularized soft tissue without inclusion of any rectus abdominis muscle and fascia and minimizes donor-site morbidity. One perforator with significant flow can perfuse the whole flap. For large flap, a perforator of the medial row provides better perfusion to zone-4 than one of lateral row and, if diameter of perforator is small, $2{\sim}3$ perforators can be used. According to the condition of recipient-site, thin flap can be harvested. As DIEP free flap has many advantage, perforator topography will be useful in increasing clinical usage of DIEP free flap.

• Journal of Veterinary Clinics
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• v.37 no.2
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• pp.91-95
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• 2020

A 13-year-old, intact male, Yorkshire terrier dog with oliguria and hematuria was presented to the Small Animal Clinic at the Gyeongsang National University animal medical center. There were no remarkable findings on serum chemistry values and complete blood counts. Abdominal radiographs revealed mild elevation of the descending colon at the pelvic level. On the excretory urographic images, a large filling defect was identified in urinary bladder with narrow urinary bladder wall contact and there were no remarkable findings in kidneys and ureters. The abdominal ultrasonography revealed that an irregularly marginated, heterogeneous mass in urinary bladder, central cavitary lesion and mild vascular flow were also observed. Computed tomography showed a heterogeneously attenuated mass within urinary bladder. The mass was surgically excised, and leiomyosarcoma was confirmed by histopathological examination. The patient was followed up for two months and there were no complications. This case is of interest because of the unusual findings of leiomyosarcoma of urinary bladder in a small breed dog.

• The Korean Journal of Nuclear Medicine
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• v.24 no.2
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• pp.279-285
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• 1990

Simultaneous presence of ascites and pleural effusion has been documented in patients with cirrhosis of the liver, renal disease, Meigs' syndrome and in patients undergoing peritoneal dialysis. Mechanisms proposed in the formation of pleural effusion in most of the above diseases are lymphatic drainage and diaphragmatic defect. But sometimes, hepatic hydrothoraxes in the absence of clinical ascites and pleural effusion secondary to pulmonary or cardiac disease are noted. It is not always possible to differentiate between pleural effusion caused by transdiaphragmatic migration of ascites and by other causes based soly on biochemical analysis. Authors performed radionuclide scintigraphy after intraperitoneal administration of $^{99m}Tc-labeled$ colloid in 23 patients with both ascites and pleural effusion in order to discriminate causative mechanisms responsible for pleural effusion. Scintigraphy demonstrated the transdiaphragmatic flow of fluid from the peritoneum to pleural cavities in 13 patients correctly. In contrast, in 5 patients with pleural effusion secondary to pulmonary, pleural and cardiac diseases, radiotracers fail to traverse the diaphragm and localize in the pleural space. Ascites draining to mediastinal lymph nodes and blocked passage of lymphatic drainage were also clarified, additionaly. Conclusively, radionuclide peritoneal scintigraphy is an accurate, rapid and easy diagnostic tool in patients with both ascites and pleural effusion. It enables the causes of pleural effusion to be elucidated, as well as providing valuable information required when determining the appropriate therapy.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.47.1-47.1
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• 2011

We report on a direct measurement of two-dimensional chemical and electrical distribution on the surface of photovoltaic Cu(In,Ga)$Se_2$ thin-films using a nano-scale spectroscopic and electrical characterization, respectively. The Raman measurement reveals non-uniformed surface phonon vibration which comes from different compositional distribution and defects in the nature of polycrystalline thin-films. On the other hand, potential analysis by scanning Kelvin probe force microscopy shows a higher surface potential or a small work function on grain boundaries of the thin-films than on the grain surfaces. This demonstrates the grain boundary is positively charged and local built-in potential exist on grain boundary, which improve electron-hole separation on grain boundary. Local electrical transport measurements with scanning probe microscopy on the thin-films indicates that as external bias is increases, local current is started to flow from grain boundary and saturated over 0.3 V external bias. This accounts for carrier behavior in the vicinity of grain boundary with regard to defect states. We suggest that electron-hole separation at the grain boundary as well as chemical and electrical distribution of polycrystalline Cu(In,Ga)$Se_2$ thin-films.

• The Journal of Engineering Research
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• v.2 no.1
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• pp.165-174
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• 1997

It is not possible to define the earth's interior because of it complicity. However, it can be interpreted directly and/ or indirectly. Geophysics is the subject of this study. To study the possibility of construction supervision by geophysical method, geophysical prospecting was performed and studied at the SamYang pumping well area in Cheju Island, where, although underground dam was constructed, the saline water invade the pumping well area. This study focuses on the construction supervision by electrical measurements. Two electric resistivity survey lines are installed in the pumping well site, and at each line electric survey was conducted at ebb and flow tides. To increase the data quality SP (self-potential) survey was also performed. As a result the geophysical exploration methods explained the defect of construction well, and It shows that geophysical probe can be a useful tool for the construction supervision.