• 방사성폐기물학회지
• /
• 제10권1호
• /
• pp.1-11
• /
• 2012

Rorabaugh(1953)에 의해 재정리된 단계양수시험 해석해 $s_w=BQ+CQ^p$는 단열암반대수층에서 비선형으로 증가하는 수위강하에 매우 적합하며, 현장에서 관측된 수위강하 값과 추정된 수위강하 사이의 제곱근 평균제곱오차(RMSE) 값이 매우 낮음을 보여주었다. 우물수두손실($CQ^p$)의 $C$ 값은 $3.689{\times}10^{-19}{\sim}5.825{\times}10^{-7}$, $P$ 값은 3.459~8.290의 범위로 산정되었으며, 지표로부터 하부심도로 내려 갈수록 양수율 증가에 따른 수위강하는 매우 크게 나타났다. 단열암반대수층에서의 우물수두손실은 다공질매질에서와 달리 단열특성(단열의 틈, 간격, 상호 연결성)에 의한 영향으로 나타나므로, 우물수두손실의 $C$ 와 $P$ 값은 단열암 반대수층의 난류구간과 고 저 투수성 단열암반의 특성을 해석하는데 매우 중요하다. 그 결과, 우물수두손실 항의 $C$ 와 $P$ 값에 대한 회귀분석 결과로부터 암반대수층의 난류구간과 수리특성의 관계가 파악되었으며, $C$ 와 $P$ 값의 관계가 단열암반대수층의 수리특성 해석에 있어 매우 유용함을 확인할 수 있었다.

• 복식문화연구
• /
• 제12권6호
• /
• pp.1021-1030
• /
• 2004

The purpose of this study was to develop and make the head form by setting the region of the head for detailed measurement of the head to make the type of closely fit hat and typifying the head form of Korean women's with each region of the head based on the measurements of each region of the head according characteristics. A total of 285 Korean women's in the age group of 18 to 35 years old. It were measured through the direct measurement method by selecting 67 measurement items. As a result of the findings obtained from cluster analysis could be classified into 3 type. Type 1($46\%$) is U-shaped form, that is high in head height on sides and circumference is smallest, whose facial region and occiput is flattest of three types. Type 2($22.4\%$) is inverted triangle form, that is flat in head ridge, low in head height on sides and wide in the frontal width. Type 3($31.6\%$) is oval form, that is largest in size, has the projected occiput and is of three-dimensional form.

• 대한두경부종양학회지
• /
• 제33권2호
• /
• pp.101-105
• /
• 2017

Mammary analogue secretory carcinoma (MASC) of the salivary gland is a newly classified pathologic entity since 2010. Prior to its recognition, MASC was diagnosed as low-grade cystadenocarcinoma, acinic cell carcinoma, and mucoepidermoid carcinoma. MASC shares common histological and genetic characteristics with secretory carcinoma of the breast and has a distinct feature of the ETV6-NTRK3 fusion gene. Treatment of MASC in salivary gland is mainly wide surgical resection of the tumor. Prognosis of MASC is similar to other low-grade salivary gland carcinomas. Herein, we report a case of MASC developed in a parotid gland with a review of the literature.

• 한국소음진동공학회논문집
• /
• 제18권9호
• /
• pp.905-912
• /
• 2008

Notion sickness is well known to be caused by long time exposure to the very low frequency motion in the multiple axes of human body Since the vestibular system for the perception of low frequency motion is located in the head, accurate measurement of 6 degree of freedom head motion is of great importance. In this study, the measurement system consisting of a safety helmet and 9 translational accelerometers was constructed for the estimation of 3 translational and 3 rotational motions of human head. Since estimation errors of 3 rotational components can be significantly magnified even by small offset of the sensitivity axis from the geometric center of an accelerometer, accurate measurement of sensitivity axis must be preceded. The method for accurate estimation of the offset was proposed, and the effect of offset on the estimation of angular acceleration was investigated.

• 대한전자공학회논문지SD
• /
• 제49권1호
• /
• pp.35-42
• /
• 2012

본 논문은 광선로 대신 Ethernet을 이용하여 저가형 WiMAX remote radio head (RRH)를 구현한 내용을 담고 있다. 간략화된 프레임 형식을 적용하여 최대 전송률이 상대적으로 낮은 Ethernet 선로의 사용 효율을 극대화하면서 기지국과 RRH들 사이에 데이터 전송이 이루어지도록 하였다. 또한 원격지에 설치되는 기지국과 RRH들이 동시에 무선데이터 송수신할 수 있도록 장치 간 동기화기법을 적용하였다. 설계된 내용은 FPGA 상에 구현되었으며 WiMAX Femtocell과 연동하여 정상적으로 무선데이터를 송수신함을 보였다.

• 한국생산제조학회지
• /
• 제25권4호
• /
• pp.301-306
• /
• 2016

High speed polishing can kinematically increase the polishing removal rate by using the conventional Preston equation, especially for hard substrates such as sapphire or diamond. However, high speed effects should be clarified beforehand considering the lubrication state and process parameter variations. In this paper, we developed a polishing experimental method and apparatus to determine the lubrication state by measuring the real time friction coefficient using two load cells. Through experiments, we obtained a boundary lubrication state above 0.35 of the friction coefficient by using low table speed and high polishing load, indicating a synchronized stable behavior in polishing head rotation. However, larger Stribeck indexes by a high speed above 200 rpm can generate a hydrodynamic lubrication state below 0.25 of the low friction coefficient. This causes the polishing head rotation to stop. A forced and synchronized head rotation is required for high speed polishing.

• 대한두경부종양학회지
• /
• 제37권2호
• /
• pp.61-65
• /
• 2021

Epithelial-myoepithelial carcinoma is rare, low-grade malignant neoplasm that compromises approximately 1% of all salivary gland neoplasms. We reported a 68-year-old woman with epithelial-myoepithelial carcinoma in the parotid gland. We analyzed demographic and clinicopathological characteristics of salivary gland epithelial-myoepithelial carcinoma which has been reported in 33 cases in Korea from 1992 to 2017, and compared this result to overseas retrospective cohort studies. There was no significance in terms of mean age at diagnosis, the predominance of females, low frequency in regional lymph nodes, and distant metastasis between the two groups. However, T classification and AJCC stage at diagnosis in domestic cases are more advanced than those of overseas cases. Although the recurrence rate in domestic cases has been reported lower than that of overseas, further study may be needed considering that the follow-up period after treatment is short in domestic cases.

• 한국방사선학회논문지
• /
• 제17권7호
• /
• pp.1133-1138
• /
• 2023

본 연구는 SAR의 최적화를 위해 다양한 시퀀스 환경에서 영상 변수와 전자파흡수율 (SAR)의 관계를 분석하였다. 이를 위해 T2, T1, STIR, T1 FLAIR 그리고 T2 FLAIR 시퀀스를 대상으로 장비에서 계산된 전신(whole body, WB) SAR와 두부 (head) SAR을 측정하였다. 그리고 영상 단면의 수와 재위상화 RF의 숙임각(FA)을 조절하며 SAR를 평가하였다. 그 결과, 모든 시퀀스에서 영상 단면의 수가 증가할수록 SAR는 증가하였다. T1과 T1 FLAIR는 상관계수(r)가 각각 0.876, 0.876 (WB SAR, head SAR), 0.867, 0.867 (WB SAR, head SAR)이었고 STIR는 0.898, 0.899 (WB SAR, head SAR)로 가장 높은 연관성을 보였다 (p<0.05). 재위상화 RF의 FA을 증가시키며 적용하였을 때, WB SAR와 head SAR는 모든 시퀀스에서 전반적으로 상승하였다. T1, T2 시퀀스에서 상관계수(r)가 각각 0.897, 0.898 (WB SAR, head SAR)과 0.914, 0.915 (WB SAR, head SAR)로 높은 연관성을 보인 반면, 반전회복기법을 적용된 시퀀스에서는 상대적으로 FA 증가에 덜 민감한 양상을 보였다. 따라서 비교적 TR이 낮은 시퀀스 환경에서는 단면의 개수를 최소화하고 고속스핀에코기법을 적용하여 동작 비율이 높은 시퀀스 환경에서는 재위상화 RF의 FA을 줄이는 것이 SAR를 줄이는 데 효과적이다.

• 한국자동차공학회논문집
• /
• 제7권9호
• /
• pp.203-211
• /
• 1999

The research committee for automobile repairs (RCAR), an international body of insurance research centers, has adopted the typical low speed crash test based on an average damage level in crash accidents to estimate the damageability , repairability and safety. The characteristics of body acceleration and the probability of injury are investigated based on damaged components, accelerations of body and injured dummy to analyze damageability and the driver's safety under low speed crash environment. It is found from the experimental results that the probability of head and thorax injuries are very low comparing to the injury criteria of FMVSS No.208. Furthermore, it is suggested that the deployment of airbag may not be necessary at RCAR low speed frontal crash test.

• 대한두경부종양학회지
• /
• 제30권2호
• /
• pp.87-89
• /
• 2014

Epidermal cysts in mouth floor are rare. There could be confusions in diagnosis due to location and low incidence. For diagnosis, imaging study and cytology are necessary. The treatment of choice is complete excision intraorally or externally and the recurrence is rare. Some authors prefer sclerotherapy, but the follow up is necessary for malignant change. We report two cases of epidermoid cyst in submental area excised externally with literature review.