• Journal of Radiation Protection and Research
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• 제34권2호
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• pp.43-48
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• 2009

When the PDD (percentage depth dose) in the megavoltage beams is measured in the water phantom, the polarity and ion recombination effects of ionization chambers with depth in water are not usually taken into consideration. We try to investigate if those variations with depth should be taken into consideration or could be ignored for the thimble type semiflex ionization chamber (PTW $31010^{TM}$, SN 1551). According to the recommendation of IAEA TRS-398, the 4 representative depths of $d_s$, $d_{max}$, $d_{90}$ and $d_{50}$ were used for the electron beams. For the photon beams, the 4 depths were arbitrarily chosen for the photon beams, which were $d_s$, $d_{max}$, $d_{10}$ and $d_{20}$. For the high energy photon beam both polarity and ion recombination factors of the chamber with depth in water gives the good agreements within the maximum $\pm$0.2%, while the $C_{polS}$ with depth came within the maximum $\pm$ 0.4% and the $C_{IRS}$ within the maximum $\pm$0.6% in every electron beam used. This study shows that PDI (percentage depth ionization) could be a good approximation to PDD for the chamber used.

• Journal of Korean Vacuum Science & Technology
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• 제6권1호
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• pp.8-11
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• 2002

Ni, Si and $SiO_2$ films were implanted by 350 keV B $i_{+}$ ions at room temperature with fluences of 1$\times$10$^{16}$ and 2$\times$10$^{16}$ ions/c $m^2$ The depth distributions of implanted B $i^{+}$ ions in Ni, Si and $SiO_2$ films were by investigated by Rutherford backscattering. The results show that the depth distributions of implanted B $i^{+}$ ions into Ni, Si and $SiO_2$ films have obeyed nearly Gaussian distributions. The maximum difference between experimental and calculated values is less than 18 % for mean projected range. Experimental range straggling deviated significantly from calculated value. The possible reasons are discussed.sed.d.

• 한국안전학회지
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• 제29권2호
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• pp.7-11
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• 2014

The electric shock victims were predominantly male, and more than half of the victims were found in companies with less than five employees in terms of the scale of company, and also more than half of victims had less than one month of experience for work experience. Considering the category of industry, more than half of the victims were engaged in construction, and considering the subcategory of industries, more than 60% of electric shock victims were found in building and other construction works. This study intended to conduct an in-depth analysis on the cause of electric shock accidents to provide basic data for policy proposing taking into considering the characteristics such as the electric shock path, low voltage, grounding and protection of workers. Also this study conducted an in-depth analysis of electric shock accidents for the past eleven years taking into account the necessity of a long-term plan.

• 물과 미래
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• 제20권3호
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• pp.237-245
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• 1987

경사정지수역으로 유입되는 밀도류의 거동이 흐름의 지배방정식인 연속방정식 운동량보존식 및 추적물수송식에 의하여 수치적으로 해석된다. 최대여행거리와 안정 plunge point는 바닥경사와 유입밀도 Froude 수 $Fr_e$에 지배를 받는다. 또한 그들은 바닥밀도류의 상부나 plunge point의 하류에 형성된 와와 밀접한 관계가 있다. Plunge depth는 바닥경사와 $Fr_e$의 함수이고, 본 수치실험에서 얻은 plunge depth는 발표된 실험자료나 해석해와 비교적 잘 맞았으며 이에 관한 예측식이 유도되었다.

• 한국유체기계학회 논문집
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• 제13권6호
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• pp.63-70
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• 2010

Shallow water withdrawal systems have been replaced with a selected withdrawal system to keep stable raw water quality in spite of occurrence of algae and muddy inflow. Before reconstruction of the water intake tower in Yongdam reservoir supplying water to Gosan water treatment facility, we have predicted flow patterns of inflowing water into the water intake tower for various withdrawal conditions. It has been predicted that the water in the withdrawal layer is significantly inflowed from the front with fast velocity into the water intake tower irrespective of withdrawal depth, while the water away from the withdrawal layer is withdrawed a little from the side with slow velocity.

• 대한전자공학회논문지
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• 제17권5호
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• pp.22-27
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• 1980

새로운 불순물(dopant) 원료인 스핀온 쏘스를 사용하여 붕소를 실리콘천에 이단계 확산시키는 공정을 검토하였다. predeposition후의 확산충의 두께의 drive-in 확산후의 두께에 비하여 무시할 수 없이 큰 경우에 대하여 이단계 확산공정이 끝난 후의 확산층의 두께를 예측할 수 있는 간단한 방법을 제안하였다. 제안된 방법에 의하여 불순물 확산충의 두께를 예측하였으며 그 결과를 실험적으로 측정된 값과 비교하였다.

• 기술사
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• 제44권1호
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• pp.44-47
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• 2011

Huge amount of energy produced by an underground nuclear test is released into the surrounding rock. Depending on the properties of the bed rock surrounding the detonation and overlaying it a variety of effects can occur. At some particular depth the increasing amount of material thrown upward is exactly balanced by the decreasing fraction escaping the crater, the crater volume reaches to a maximum. This depth is called the optimum depth of burial and varies somewhat with the geology of the site, being greater for less dense and structurally weaker material.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1203-1204
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• 2013

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1390-1403
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• 2016

Facial expression recognition (FER) plays a very significant role in computer vision, pattern recognition, and image processing applications such as human computer interaction as it provides sufficient information about emotions of people. For video-based facial expression recognition, depth cameras can be better candidates over RGB cameras as a person's face cannot be easily recognized from distance-based depth videos hence depth cameras also resolve some privacy issues that can arise using RGB faces. A good FER system is very much reliant on the extraction of robust features as well as recognition engine. In this work, an efficient novel approach is proposed to recognize some facial expressions from time-sequential depth videos. First of all, efficient Local Binary Pattern (LBP) features are obtained from the time-sequential depth faces that are further classified by Generalized Discriminant Analysis (GDA) to make the features more robust and finally, the LBP-GDA features are fed into Hidden Markov Models (HMMs) to train and recognize different facial expressions successfully. The depth information-based proposed facial expression recognition approach is compared to the conventional approaches such as Principal Component Analysis (PCA), Independent Component Analysis (ICA), and Linear Discriminant Analysis (LDA) where the proposed one outperforms others by obtaining better recognition rates.

• 한국도로학회논문집
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• 제19권2호
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• pp.1-6
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• 2017

PURPOSES : Pavement textures can be categorized into four according to wavelength: microtexture, macrotexture, megatexture (roads), and roughness. Pavement surface texture influences a number of aspects of tire-pavement interaction such as wet-weather friction, tire-pavement noise, splash, spray, tire-wear, and rolling resistance. In particular, macrotexture is the pavement surface characteristic that considerably impacts tire-pavement noise. In general, it can be demonstrated that tire-pavement noise increases with the increase of texture depth and wavelength. Recently, mean profile depth (MPD) and wavelength have been used to evaluate tire-pavement noise. This study aimed to identify the relationship between mean profile depth and average wavelength for asphalt pavement based on the information obtained on a number of asphalt pavement sections. METHODS : Profile data were collected from a number of expressway sections in Korea. In addition, mean profile depth and average wavelength were calculated by using this profile data. Statistical analysis was performed to determine the correlationship between mean profile depth and average wavelength. RESULTS:This study demonstrates a linear relationship between mean profile depth and average wavelength for asphalt concrete pavement. CONCLUSIONS :The strong relationship between mean profile depth and average wavelength of asphalt pavement was determined in this study.