• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.453-462
• /
• 1994

Variation of seismic wave field in a multi-layered attenuating elastic half space is studied by the propagator matrix method and point source models of which fault-slip functions are defined as ramp functions. In this paper, the earth is modeled as being composed of horizontally stratified layers, with uniform material properties for each layer. The partial differential equations for the seismic motion in each layer are solved using a Fourier Hankel transform approach. Time histories and frequency contents of accelerations and displacements due to a vertical dip-slip and strike-slip point source located in the underlain half space are calculated at the layer interfaces using the developed programs and their characteristics are represented.

• Journal of Biomedical Engineering Research
• /
• v.38 no.5
• /
• pp.219-226
• /
• 2017

Penalized-likelihood (PL) reconstruction methods for transmission tomography are known to provide improved image quality for reduced dose level by efficiently smoothing out noise while preserving edges. Unfortunately, however, most of the edge-preserving penalty functions used in conventional PL methods contain at least one free parameter which controls the shape of a non-quadratic penalty function to adjust the sensitivity of edge preservation. In this work, to avoid difficulties in finding a proper value of the free parameter involved in a non-quadratic penalty function, we propose a new adaptive method of space-variant smoothing with a simple quadratic penalty function. In this method, the smoothing parameter is adaptively selected for each pixel location at each iteration by using the image roughness measured by a pixel-wise standard deviation image calculated from the previous iteration. The experimental results demonstrate that our new method not only preserves edges, but also suppresses noise well in monotonic regions without requiring additional processes to select free parameters that may otherwise be included in a non-quadratic penalty function.

• The Journal of the Korea Contents Association
• /
• v.5 no.5
• /
• pp.59-64
• /
• 2005

The biometrics of iris is a very accurate authentication method. The biometrics of iris can recognize and identify a person for shortly. But the image of iris is changed by transformation of body in the life. The existing iris authentication system has problem that can be mis-recognized. In this paper, we proposed and implemented Renewable Iris Authentication Algorithm(RIAA) for biometrics in authentication system. This algorithm tries to present a new way to people identification, we show contour line when shift take photograph in regular side. Namely, it generate iris code based on boundary of projection or submergence side and compared to original, so that it describes iris identification method to people identification.

• The Korean Journal of Malacology
• /
• v.9 no.2
• /
• pp.94-102
• /
• 1993

동양달팽이(Nesiohelix samarangae)의 자성생식기 중 정자낭(spermatheca)의 미세구조를 투과전자현미경을 이용하여 관찰하였다. 성체의 정자낭의 내강에서는 정자와 이와 관련된 물질들 또는 상피로부터의 분비물질들이 관찰되었다. 정자낭의 내강을 둘러싸고 있는 벽의 상피는 단층원주상피로서 내강과 연한 세포의 원형질막은 미세융모를 가지고 있었으며 섬모는 가지고 있지 않았다. 이 미세융모들의 기부에서는 고배율 하에서 pinocytotic vesicle들이 관찰되었고 때로 세포의 분비물을 세포 밖으로 방출하는 모습도 관찰되었다. 세포들의 상부세포질에는 많은 수의 mitochondria가 있었고, 때로 분비과립과 lysosomd들이 존재하기도 하였다. 이들보다 아래에는 잘 발달한 골지체와 과립소포체(RER)들이 있었다. 이 부위에서 분비과립들이 많이 형성되어 있는 모습이 세포에 따라 관찰되었고, 그 아래에 즉, 각 세포의 하반부 세포질에 상하로 긴 핵이 관찰되었다. 세포의 기부 원형질막은 상부 세포질 내로 깊게 그리고 수없이 많이 주름을 이루고 있어 인접한 세포와의 경계를 구분할 수 없을 정도였다. 기저막의 아래에는 근육다발과 색소세포들이 결합조직 내에서 관찰되었고, 정자낭의 외막은 큰 액포로 인하여 세포질들이 원형질막 주변으로 밀려나 있는 특이한 세포들로 이루어져 있었다. 정자낭의 기능은 정자를 일시 저장하며 정자낭 상피에서 분비되는 소화액들로 정자를 일차적으로 세포외 소화하고 소화되지 않은 물질들을 흡수하여 이차적으로 세포내소화하는 것으로 생각된다.

• Korean Journal of Head & Neck Oncology
• /
• v.25 no.2
• /
• pp.143-145
• /
• 2009

신경초종은 전신의 말이집신경 중 어디에서나 발생할 수 있는 말초신경집 양성종양이다. 이 종양이 비강에서 발생하는 것은 흔하지 않다. 저자들은 뇌경색으로 입원하고 있던 55세 여자환자에서 다량의 비출혈을 동반한 비강 신경집종 1예를 보고하는 바이다. 부비강 컴퓨터단층촬영사진상 좌측비강과 비인두를 채우는 비균질한 저음영의 거대 종양이 관찰되었고 뼈의 재형성 역시 관찰되었다. 내시경 생검을 시행하였다. 병리검사상, 난원형의 경계가 좋은 병변이 편평상피로 화생된 비강 점막 아래에서 관찰되었고, 종양은 물결모양의 핵을 가진 방추세포로 이루어져 있었고, 방추형의 핵들이 밀집하게 모여있는 Antoni A 부분과 세포의 수가 적으며 허술하게 뭉쳐있는 Antoni B 부분으로 이루어져 있었으며 S-100 단백질 면역염색에 양성이었다. 비강의 신경초종으로 진단하였다. 따라서, 흔하지 않게 접하게 되는 비강 신경초종의 임상양상, 감별진단, 및 치료에 대해 알아보고자 한다.

• Journal of Chest Surgery
• /
• v.32 no.1
• /
• pp.66-69
• /
• 1999

Bronchogenic cyst is an uncommon congenital lesion which is derived from the primitive foregut. Most bronchogenic cyst may develope at the tracheal bifurcation, both main bronchi, the lung parenchymeand the mediastinum. A 40-year old male was evaluated for dyspnea and chest tightness. Computed tomography revealed a well dermarcated, 7.2 ${\times}$ 7.9 cm sized, homogeneous mass compressing the left atrium. 2D-echo showed grade III mitral regurgitation. We completely removed the cystic mass and then confirmed the bronchogenic cyst in the pathological diagnosis. During the follow up period, the patient progressed well without any symptoms and showed grade I mitral regurgitation on the 2D-Echo. Therefore, we report a case of the bronchogenic cyst causing grade III mitral regurgitation.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.4
• /
• pp.580-585
• /
• 1999

Neurilemmoma is a benign nerve sheath tumor derived from Schwann cells and occurs in the head, neck, flexor regions of the extremities, posterior mediastinum but extremely rare in the chest wall. They occur at all ages but are most common in persons between the ages of 20 and 50 years and develop spontaneously or possible as a result of trauma or irritation. The diagnosis of a neurilemmoma is confirmed histologically by the findings of Verocay bodies, Antoni A and B tissue patterns and the presence of S-100 protein. We experienced a case of chest wall neurilemmoma which was treated by local excision and report it with a brief review of the literature.

• Explosives and Blasting
• /
• v.40 no.1
• /
• pp.17-28
• /
• 2022

Electrical pulse disintegration(ED) is known as an efficient technology for recovering valuable resources by inducing dielectric breakdown in solids to separate mineral interfaces in ores among the crushing technologies by high voltage discharge. In this study, ED crushing experiment and mechanical crushing experiment of sulfide minerals were performed, and SEM analysis and Microfocus X-Ray CT of the crushed product were performed in order to analyze the disintegration characteristics of zinc minerals exist in the sulfide minerals by the shock wave generated in the solid by high voltage discharge.

• Journal of the Korean Society of Radiology
• /
• v.83 no.2
• /
• pp.387-393
• /
• 2022

Primary pulmonary malignant melanoma is an extremely rare type of melanoma. The radiologic features of primary pulmonary malignant melanoma are nonspecific; however, it almost always presents as a well-demarcated round or lobulated solitary solid nodule or mass. Herein, we report the case of a 78-year-old male with primary pulmonary malignant melanoma that was mistaken for primary pulmonary adenocarcinoma with lepidic growth and was seen as bilateral multiple subsolid nodules on CT.

• The Journal of Engineering Geology
• /
• v.7 no.2
• /
• pp.113-126
• /
• 1997

Electrical resistivity methods of dipole - dipole array profiling and Schiumberger array sounding were tested on a segment of the Woraksan granitic batholith for the research into the imaging of irregular attitudes of fracture zones in the crystaaline rock in terms of processing and interpretation schemes. By the dipole - dipole array method, inhomogeneities such as small scale of fracture zones were properly delineated down at some depth even within hard rock environment. Fracture zones were interpreted to be at the boundaries between the high amplitude zone and very low amplitude zone in the resistivity plot and they were also successfully outlined in two - dimensional layer and pseudo - three - dimensional volume constructed by the incorporation of vertical sounding data. The surface location of the fracture zones was correlated by the zero - crossing point in the VLF(very low frequency) electromagnetic data. Pseudo - three - dimensional attitudes of fracture zones were efficiently illuminated by optimum projection angle. The mean of bulk resistivity for the Woraksan granite and the near fracture zones is estimated to be approximately of 4,000 ohm - m which is much higher than the value of 700 ohm - m for the Rwachunri limesilicate environment. This difference is due to both the rock type, i.e., biotite granite vs limesilicate, and the occurrence of secondary openings of fold and fault associated with the intrusion of granite. In this study statistical analyses on the resistivity color plot were performed in terms of three representative statistical moments, i.e., standard deviation, skewness, and kurtosis. The fracture zones in the standard deviation plot were characterized by the higher value, compared to the value of homogeneous portion. The upper boundary of the high resistivity zone was also successfully delineated in the skewness and kurtosis plots.