• Nuclear Medicine and Molecular Imaging
• /
• v.43 no.5
• /
• pp.443-450
• /
• 2009

Purpose: Conventional image reconstruction uses simplified physical models of projection. However, real physics, for example 3D reconstruction, takes too long time to process all the data in clinic and is unable in a common reconstruction machine because of the large memory for complex physical models. We suggest the realistic distributed memory model of fast-reconstruction using parallel processing on personal computers to enable large-scale technologies. Materials and Methods: The preliminary tests for the possibility on virtual manchines and various performance test on commercial super computer, Tachyon were performed. Expectation maximization algorithm with common 2D projection and realistic 3D line of response were tested. Since the process time was getting slower (max 6 times) after a certain iteration, optimization for compiler was performed to maximize the efficiency of parallelization. Results: Parallel processing of a program on multiple computers was available on Linux with MPICH and NFS. We verified that differences between parallel processed image and single processed image at the same iterations were under the significant digits of floating point number, about 6 bit. Double processors showed good efficiency (1.96 times) of parallel computing. Delay phenomenon was solved by vectorization method using SSE. Conclusion: Through the study, realistic parallel computing system in clinic was established to be able to reconstruct by plenty of memory using the realistic physical models which was impossible to simplify.

• The Journal of Engineering Geology
• /
• v.8 no.1
• /
• pp.35-49
• /
• 1998

To interpret the movement historv of the Yangsan fault, the paleostresses were analyzed from about 1,000 striated small faults and 330 extension joints which were measured from 37 sites near and along the strike of the Yangsan fault from Yangsan-si, Kyeongsangnam-do to the Shinkwang-myeon, Kyeongsangbuk-do. Six sequential tectonic events have boen established as followings: (I) NW-SE extension, (Il) ENE-WSW compression and NNW-SSE extension, (III) NW-SE compression, (W) ENE-WSW extension, (V) E-W comoression and N-S extension, and (VI) NNE-SSW compression and(VI) NNE-SSWextension. The movement history of the Yangsan fault rnrning in NNE direction were inteepreted based on these six sequential stress fields. The initial feature of the Yangsan fault was formed at the first stage with the development of extension fractures by tectonic event (I) of NW-SE extension. The fault was acted continuously with a right-1ateral strike-slip movement by tectonic event( II) closely related to event( I). The movements had been continued until the Late Miocene. This age was the most active period in faulting. The left-lateral strike-slip movement was followed by subsequent tectonic events (ffi) and (IV). The activity of the Yangsan fault was suspended temporarily by compression of tectonic event (V) which was perpendicular to the strike of the fault. This period might be very short and the magnitude of the tectonic was also small. In the last stage, the fault acted with slight extension or right-lateral moveenent by tectonic event (VI).

• Korean Journal of Occupational Health Nursing
• /
• v.10 no.1
• /
• pp.74-92
• /
• 2001

This study was carried out to investigate the types of health documents for nurses, the content of informations in the documents, and writing behaviors of occupational health nurses. Health documents were collected from 7 nurses who were working in 7 group occupational health agencies (GOHA) located at Seoul and Inchon area in Korea. The collected health documents written in January to June 1999 were analyzed, and revealed the following results. 1) The occupational health nurses were using 9 to 18 different types of health documents. The contents of the documents were considered quite similar to each other with slightly different headings and items to record. Among different types of health documents. Health Management Card for Workplace', Nursing performance sheet and Workplace environmental checklist were in common among nurses and were used for content analysis. 2) The 'Health Management Card for Workplace' was the only formal sheet of small-scale-enterprises (SSE) for health management, in which health and safety related information was recorded. The information on nursing services were recorded on the Nursing performance sheet, which has slightly different names on each type with similar contents. The Workplace environment checklist was for the information on general work environment management and mainly status of workplace hygiene. This checklist is to be used by or with nurses among the 3 types health professional team such as doctor, hygienist, and nurse, but it seemed not being used frequently by nurses. 3) Analysis on recording tendencies of nurses revealed that the writing styles of occupational health nurses were associated with 'memo' using a few number of words and short sentences. The amount of information by this kind of recording style was considered not enough for health management situation. The possible reasons for nurses to use this writing style might be insufficient time for recording and improper designed format of health documents. Because nurses working in SSE spend more time on the roads to visit workplaces, nurses may not found enough time for recording properly within their working time. In addition, the health records were designed to focus on the frequency of nurse's performance in certain types of work rather than on the method they used to deal with health problems. In conclusion, this study suggests that some steps are necessary to develop health documents and recording system which is appropriate to occupational health nurses. The educational need for nurses on appropriate recording behavior is also recommended.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.3
• /
• pp.270-275
• /
• 2006

The cultivated pearls collected for the study were pretreated through the removal of contaminants and the surface bleaching for easy dyeing. Coloring of pearls are necessary after selecting dyes adsorbable to the Conchiolin layer, a kind of hard protein formed in the seawater, covering the surface of the pretreated pearls. Dyes adsorbable to the Conchiolin layers are mostly basic dyes such as Rhodamine 6G(R6G), Rhodamine B(RB), Methylene Blue(MB) etc. and the binary and ternary competitive adsorption were performed by mixing two or three dyes together. The multi-dye adsorption data were compared with the predictions from the ideal adsorbed solution theory(IASI) combined with the single-dye adsorption model, the Langmuir or the Redlich-Peterson(RP) model. The quality of prediction was compared by using determination coefficient($R^2$) and standard deviation(SSE) values. Predictions from the IAST were found to be in good agreement with the data for the R6G/RB binary adsorption to the pearl layers not fractionated with their size, except for the adsorption data for RB at high concentrations. Among the three binary adsorption systems, R6G/RB, R6G/MB, and MB/RB, only the RB sorption data in the R6G/RB binary system was in poor agreement with the IAST prediction. Competitive adsorption data in ternay systems were in good agreement with the predictions from the IAST except for the RB data.

• Journal of Korean Society of Disaster and Security
• /
• v.12 no.1
• /
• pp.1-9
• /
• 2019

The basic analysis of Soil and structural mechanics for the bridge substructure affected by the flow of water is sufficient in the construction of such bridges, but the stability of scour resulting from hydraulic phenomena is insufficient. In addition, it is not enough to estimate the scour depth of the bridge which reflects the watershed characteristics of the domestic river because it uses the formula for calculating the scour depth of the overseas piers in calculating the scour depth of the bridge. In this study, the application of the CSU (1993) formula, which is currently applied to the national river design criteria, was reviewed between the two formulas after calculating the scour after calculating the scour by applying another bridge deck scour calculation formula to take into account the uncertainty in the calculation of scour. In this study, in addition to the CSU (1993) formula, which is currently applied to Korean river design criteria, another scour depth calculation formula is applied to calculate uncertainty in scour depth calculation, was reviewed between the two formulas. The review confirmed that the SSE (%) showed a difference of at least 2.08%, up to 91.23%, and SSEn(%) at least 0.19%, up to 415.91%, when compared to the measured depth of the pier based on the hydraulic model experiment and the depth of the pier calculated with the nine scour depth formulas in use. In other words, it is confirmed that there are many differences between the scouring formulas of piers. The results of this study are expected to be used to estimate scour depth in future river design.

• Journal of the Korean Institute of Gas
• /
• v.25 no.1
• /
• pp.20-29
• /
• 2021

During multi-stage fracturing in a low permeable shale formation, stress interference occurs between the stages which is called the "stress shadow effect(SSE)". The effect may alter the fracture propagation direction and induce ununiform geometry. In this study, the stress shadow effect on the hydraulic fracture geometry and the well productivity were investigated by the commercial full-3D fracture model, GOHFER. In a homogeneous reservoir model, a multi-stage fracturing process was performed with or without the SSE. In addition, the fracturing was performed on two shale reservoirs with different geomechanical properties(Young's modulus and Poisson's ratio) to analyze the stress shadow effect. In the simulation results, the stress change caused by the fracture created in the previous stage switched the maximum/minimum horizontal stress and the lower productivity L-direction fracture was more dominating over the T-direction fracture. Since the Marcellus shale is more brittle than more dominating over the T-direction fracture. Since the Marcellus shale is more brittle than the relatively ductile Eagle Ford shale, the fracture width in the former was developed thicker, resulting in the larger fracture volume. And the Marcellus shale's Young's modulus is low, the stress effect is less significant than the Eagle Ford shale in the stage 2. The stress shadow effect strongly depends on not only the spacing between fractures but also the geomechanical properties. Therefore, the stress shadow effect needs to be taken into account for more accurate analysis of the fracture geometry and for more reliable prediction of the well productivity.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.243-249
• /
• 2020

This study analyzes the earnings management that can occur in the process of public offering in the process of SMEs reducing cost of capital, risks and seeking opportunities for direct financing. Since a company is subject to strict supervision during the IPO process, it is possible to prevent the phenomenon that the company value evaluated in the market is underestimated, or to perform earnings management in consideration of overestimation. This study attempted to verify the degree of earnings management through discretionary accruals and actual earnings management values that can affect the earnings ratio of the IPO of a company. For this study, total accruals were calculated and analyzed through discretionary accruals, sales, costs, and actual earnings management adjustments from production activities. As a result of the analysis, discretionary accruals, which are the countermeasures for earnings management during the listing process, have a positive(+) relationship in both the stock price return and the sales adjustment value, which can be viewed as a factor that induces high valuation. As a result of this, there may be a risk of adverse selection for the benefit amount, and information asymmetry may exist for public offering stocks. This study can provide useful guidelines for evaluating corporate value to domestic SMEs and investors that do business with Chinese companies as well as China through the current and type of earnings management of Chinese listed companies.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.10a
• /
• pp.53-54
• /
• 2010

국내에서 소규모 어항의 재개발에 관광객 유치를 위한 친환경적인 기술의 적용이 본격화되고 있다. 항내수질 개선이라는 목적 하에서 외곽시설인 방파제의 선택은 항내 정온과 제체 안정성의 확보가 전제되어야 한다. 따라서 본 연구에서는 친환경방파제인 슬릿방파제의 수리특성을 파악하기 위한 수리모형실험을 수행하고 그 결과를 이용하여 파랑변형 및 유동 실험을 수행하였다. 현장 적용성 확인을 위하여 선정된 구조라항은 우리나라 남해의 소규모 어항으로, SSE, S, SSW파향에 영향을 받는 지역으로, 슬릿방파제를 적용한 결과 제체안정성과 항내 정온도가 확보되는 것으로 나타났다. 이는 슬릿방파제의 특징으로 장주기파의 통과율이 뛰어나다는 점과 소파효과라는 1차적인 목적과 항만 및 연안수역에서 해수교환의 향상이라는 2차적인 목적을 동시에 만족하는 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.2
• /
• pp.728-741
• /
• 2015

Stereo vision has become an important technical issue in the field of 3D imaging, machine vision, robotics, image analysis, and so on. The depth map extraction from stereo video is a key technology of stereoscopic 3D video requiring stereo correspondence algorithms. This is the matching process of the similarity measure for each disparity value, followed by an aggregation and optimization step. Since it requires a lot of computational power, there are significant speed-performance advantages when exploiting parallel processing available on processors. In this situation, multi-core CPU may allow many parallel programming technologies to be realized in users computing devices. This paper proposes parallel implementations for calculating disparity map using a shared memory programming and exploiting the streaming SIMD extension technology. By doing so, we can take advantage both of the hardware and software features of multi-core processor. For the performance evaluation, we implemented a parallel SAD algorithm with OpenMP and SSE2. Their processing speeds are compared with non parallel version on stereoscopic streaming video. The experimental results show that both technologies have a significant effect on the performance and achieve great improvements on processing speed.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.23 no.4
• /
• pp.411-418
• /
• 2016

Purpose: The purposes of this study were to identify nursing students' levels of anxiety in simulation based nursing education and to understand the relationship of anxiety and personal satisfaction of simulation, self-efficacy, and clinical competence during simulation. Methods: This study was a descriptive study with 84 senior nursing students at a private university in South Korea. Level of anxiety was measured with STAI (the State- Trait Anxiety Inventory) prior to the stimulation practice. After the debriefing, satisfaction scores were measured with SSE (Satisfaction with Simulation Experience scale), self-efficacy scores with the modified measurement developed by Roh and Park, and scores for clinical skills with a scale developed by the Korea Association of Cardiopulmonary Resuscitation. Results: Nursing students exhibited moderate to severe anxiety in simulation practice (Mean 49.51, SD 8.60). Self-efficacy was negatively correlated to anxiety (r=-.25, p=.022). Conclusion: Decreasing students' anxiety levels needs to be addressed to increase the self-efficacy of the simulation practice.