• Geomechanics and Engineering
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• v.12 no.1
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• pp.85-109
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• 2017

The paper presents the laboratory study of clayey soil stabilized with Pond ash (PA), Rice husk ash (RHA), cement and their combination used as stabilizers to develop and evaluate the performance of clayey soil. The effect of stabilizer types and dosage on fresh and mechanical properties is evaluated through compaction tests, unconfined compressive strength tests (UCS) and Split tensile strength tests (STS) performed on raw and stabilized soil. In addition SEM (scanning electron microscopy) and XRD (X-ray diffraction) tests were carried out on certain samples in order to study the surface morphological characteristics and hydraulic compounds, which were formed. Specimens were cured for 7, 14 and 28 days after which they were tested for unconfined compression tests and split tensile strength tests. The moisture and density curves indicate that addition of RHA and pond ash results in an increase in optimum moisture content (OMC) and decrease in maximum dry density (MDD). The replacement of clay with 40% PA, 10% RHA and 4% cement increased the strength (UCS and STS) of overall mix in comparison to the mixes where PA and RHA were used individually with cement. The improvement of 336% and 303% in UCS and STS respectively has been achieved with reference to clay only. Developed stabilized soil mixtures have shown satisfactory strength and can be used for low-cost construction to build road infrastructures.

• Steel and Composite Structures
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• v.24 no.1
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• pp.1-13
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• 2017

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.693-698
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• 2016

Bruise caused by damages through physical compression and suction is one of evidences that can prove abuse or assault. It is essential for taking photography to prove a crime. Some studies about the Infrared (IR) light source have limitations that only one IR light source and one barrier filter were used. To find the best combination of filters and IR light sources, we produced suction bruise artificially and used three IR light sources and five barrier filters. Consequently, we found that the best combination is using a tungsten lamp and Kodak Wratten #18A barrier filter.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.588-596
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• 2008

For the patients' privacy, secure access control of medical images is essentially necessary. In this paper, two types of Region of Interest (ROI)-based selective encryption schemes are proposed, which concentrate on the security of crucial parts in medical images. The first scheme randomly inverts the most significant bits of ROI coefficients in several high frequency subbands in the transform domain, which only incurs little loss on compression efficiency. The second scheme employs a symmetric key encryption to encrypt selectively the ROI data in the final code-stream, which provides sufficient confidentiality. Both of two schemes are backward compatible so as to ensure a standard bitstream compliant decoder so the encrypted images can be reconstructed without any crash.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.284-286
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• 2011

Glossopharyngeal neuralgia is a relatively rare condition characterized by severe, paroxysmal episodes of lancinating pain in the tongue, throat, ear, and tonsil. This disorder is assumed to be due to compression of the glossopharyngeal nerve by vascular structures. A 47-year-old woman complaining of sharp and lancinating pain in the right periauricular and submandibular areas visited our hospital. Swallowing, chewing, and lying on her right side triggered the pain. Her neurologic examination revealed no specific abnormalities. The results of routine hematologic and blood chemistry studies were all within normal limits. Carbamazepine and gabapentin were given, but her symptoms persisted. Her pain was temporarily relieved only by narcotic pain medication. MRI showed an arachnoid cyst located in the right cerebellomedullary cistern extending to the cerebellopontine cistern. Cyst removal was performed via a right retrosigmoid approach. Lateral suboccipital craniotomy was performed using the right park-bench position. After opening the dura and cerebellopontine angle, the arachnoid cyst was exposed. The arachnoid cyst was compressing the flattened lower cranial nerves at the right jugular fossa. Her symptoms resolved postoperatively. Two months after the operation, she was completely free from her previous symptoms.

• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.853-864
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• 2017

HD padding area is essential redundancy in HD broadcasting. It is possible to use this padding area for the purpose of improving DTV broadcasting services. For utilization of this area, The bit of a service data was converted to black and white $8{\times}8$ block image. Converted block images are compressed with active video and are delivered to a receiver as only DC coefficients in a video stream. video quality is not effected by the proposed method, and service data was perfectly recovered in receiver without errors by using block average and threshold. The proposed utilization of HD essential padding area can possibly overcome the limited transmission stream rate with the bandwidth of HD broadcasting. If service data in transport or video stram were transferred using this padding area, it is possible to improve video quality with expanded video stream rate. Additionally, because the proposed methods are based on well-established standards, it is also useful for world-wide HD broadcasting systems such as ATSC, DVB, and IPTV.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.610-614
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• 2014

Like many types of scientific data, results from simulations of volcanic ash diffusion are of a clustered sparse matrix in the netCDF format. Since these data sets are large in size, they generate high storage and transmission costs. In this paper, we suggest a new method that reduces the size of the data of volcanic ash diffusion simulations by converting the multi-dimensional index to a single dimension and keeping only the starting point and length of the consecutive zeros. This method presents performance that is almost as good as that of ZIP format compression, but does not destroy the netCDF structure. The suggested method is expected to allow for storage space to be efficiently used by reducing both the data size and the network transmission time.

• Korean Journal of Cognitive Science
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• v.21 no.1
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• pp.145-156
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• 2010

This paper presents a new contents-based digital still image protection method which includes a copyright message. Since the existing method using gradient values used a pixel based $3{\times}3$ Sobel operator, it was sensitive to attacks and could not extract exact copyright message. Therefore, in this paper, we present a algorithm which uses block based OCL(Orientation Certainty Level) instead of pixel. The experimental results show that the proposed scheme not only has good image quality, but also is robust to JPEG lossy compression, filtering, sharpening, blurring and noise. Moreover, the proposed algorithm has good performance more than 10% in rotation attacks than the existing method.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2006.03a
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• pp.79-93
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• 2006

It is well known that acoustic emission (AE) is indicator of rock fracturing or damage as rock is brought to failure under the uniaxial compressive loads. In this paper, an experimental study on the source location of acoustic emission on the cylindrical specimens of granite under uniaxial compression test was made. The AE source location was made by measuring the six channel AE data. Comparing to this experiment, the numerical method is applied to model the initiation and propagation of fracture by AE using a numerical code, RFPA (Realistic Failure Process Analysis). This code incorporates the mesoscopic heterogeneity in Young's modulus and rock strength characteristic of rock masses. In the numerical models, values of Young's modulus and rock strength are realized according to a Weibull distribution in which the distribution parameters represent the level of heterogeneity of the medium. The results of the simulations show that RFPA can be used not only to produce acoustic emission similar to those measurements in our experiments, but also to predict fracturing patterns under uniaxial loading condition.

• Earthquakes and Structures
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• v.6 no.2
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• pp.181-199
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• 2014

The infill walls, whose contribution to the earthquake resistance of a structure is generally ignored due to their limited lateral rigidities, constitute a part of the lateral load bearing system of an RC frame structure. A common method for improving the earthquake behavior of RC frame structures is increasing the contribution of the infill walls to the overall lateral rigidity by strengthening them through different techniques. The present study investigates the influence of externally bonded perforated steel plates on the load capacities, rigidities, and ductilities of hollow brick infill walls. For this purpose, a reference (unstrengthened) and twelve strengthened specimens were subjected to monotonic diagonal compression. The experiments indicated that the spacing of the bolts, connecting the plates to the wall, have a more profound effect on the behavior of a brick wall compared to the thickness of the strengthening plates. Furthermore, an increase in the plate thickness was shown to result in a considerable improvement in the behavior of the wall only if the plates are connected to the wall with closely-spaced bolts. This strengthening technique was found to increase the energy absorption capacities of the walls between 4 and 14 times the capacity of the reference wall. The strengthened walls reached ultimate loads 30-160% greater than the reference wall and all strengthened walls remained intact till the end of the test.