Kim, Dae Sup;Lee, Woo Seok;Yoon, In Ha;Back, Geum Mun
The Journal of Korean Society for Radiation Therapy
/
v.26
no.1
/
pp.11-19
/
2014
Purpose : To derive the most appropriate factors by considering the effects of the major factors when applied to the optimization algorithm, thereby aiding the effective designing of a ideal treatment plan. Materials and Methods : The eclipse treatment planning system(Eclipse 10.0, Varian, USA) was used in this study. The PBC (Pencil Beam Convolution) algorithm was used for dose calculation, and the DVO (Dose Volume Optimizer 10.0.28) Optimization algorithm was used for intensity modulated radiation therapy. The experimental group consists of patients receiving intensity modulated radiation therapy for the head and neck cancer and dose prescription to two planned target volume was 2.2 Gy and 2.0 Gy simultaneously. Treatment plan was done with inverse dose calculation methods utilizing 6 MV beam and 7 fields. The optimal algorithm parameter of the established plan was selected based on volume dose-priority(Constrain), dose fluence smooth value and the impact of the treatment plan was analyzed according to the variation of each factors. Volume dose-priority determines the reference conditions and the optimization process was carried out under the condition using same ratio, but different absolute values. We evaluated the surrounding normal organs of treatment volume according to the changing conditions of the absolute values of the volume dose-priority. Dose fluence smooth value was applied by simply changing the reference conditions (absolute value) and by changing the related volume dose-priority. The treatment plan was evaluated using Conformal Index, Paddick's Conformal Index, Homogeneity Index and the average dose of each organs. Results : When the volume dose-priority values were directly proportioned by changing the absolute values, the CI values were found to be different. However PCI was $1.299{\pm}0.006$ and HI was $1.095{\pm}0.004$ while D5%/D95% was $1.090{\pm}1.011$. The impact on the prescribed dose were similar. The average dose of parotid gland decreased to 67.4, 50.3, 51.2, 47.1 Gy when the absolute values of the volume dose-priority increased by 40,60,70,90. When the dose smooth strength from each treatment plan was increased, PCI value increased to $1.338{\pm}0.006$. Conclusion : The optimization algorithm was more influenced by the ratio of each condition than the absolute value of volume dose-priority. If the same ratio was maintained, similar treatment plan was established even if the absolute values were different. Volume dose-priority of the treatment volume should be more than 50% of the normal organ volume dose-priority in order to achieve a successful treatment plan. Dose fluence smooth value should increase or decrease proportional to the volume dose-priority. Volume dose-priority is not enough to satisfy the conditions when the absolute value are applied solely.
Kim, Jin-Seop;Cho, Won-Jin;Park, Seunghun;Kim, Geon-Young;Baik, Min-Hoon
Journal of Korean Tunnelling and Underground Space Association
/
v.21
no.5
/
pp.587-609
/
2019
Short-and long-term stabilities of bentonite, favored material as buffer in geological repositories for high-level waste were reviewed in this paper in addition to alternative design concepts of buffer to mitigate the thermal load from decay heat of SF (Spent Fuel) and further increase the disposal efficiency. It is generally reported that the irreversible changes in structure, hydraulic behavior, and swelling capacity are produced due to temperature increase and vapor flow between $150{\sim}250^{\circ}C$. Provided that the maximum temperature of bentonite is less than $150^{\circ}C$, however, the effects of temperature on the material, structural, and mineralogical stability seems to be minor. The maximum temperature in disposal system will constrain and determine the amount of waste to be disposed per unit area and be regarded as an important design parameter influencing the availability of disposal site. Thus, it is necessary to identify the effects of high temperature on the performance of buffer and allow for the thermal constraint greater than $100^{\circ}C$. In addition, the development of high-performance EBS (Engineered Barrier System) such as composite bentonite buffer mixed with graphite or silica and multi-layered buffer (i.e., highly thermal-conductive layer or insulating layer) should be taken into account to enhance the disposal efficiency in parallel with the development of multilayer repository. This will contribute to increase of reliability and securing the acceptance of the people with regard to a high-level waste disposal.
Journal of The Korean Association For Science Education
/
v.41
no.3
/
pp.237-250
/
2021
Teachers play a key role in designing a students' learning experience. Teachers are asked to interpret the context in which they are located and to adjust their practice to fit circumstantial needs based on their teacher agency. In this study, we explore the emergence of teacher agency in distance learning caused by COVID-19 and we analyze factors shaping the teacher agency. For this purpose, we interviewed six secondary science teachers who practiced distance learning in 2020. Semi-constructed interviews and their artifacts were collected and analyzed. This study shows that teacher agency is captured when they respond to circumstantial change and modify their practice to achieve their professional purpose or adjust their practice in space for maneuvering or keep their practice consistent. This study also analyzes the factors that affect the emergence of teacher agency in two dimensions. One is individual and the other is contextual. In the individual dimension, educational values shaped by his/her experiences and short/long-term goals for the future support the emergence of teacher agency. In the contextual dimension, there are collaborative and flexible culture shared by the community, co-operation within the teacher community, and material support. On the other hand, in the individual dimension, the teachers' sense of their role, and no reflection for own practice constrain the emergence of teacher agency, and in the contextual dimension, performativity discourse and strong requirement without guidance constrain the emergence of teacher agency. We suggest an effective lens for establishing a strategy that support teachers' professional practice and the emergence of teacher agency.
The building process of any geological map involves linking sparse lithological outcrop information with equally sparse geometrical measurements, all in a single entity which is the preferred interpretation of the field geologist. The actual veracity of this interpretative map is partially dependent upon the frequency and distribution of geological outcrops compounded by the complexity of the local geology. Geophysics is commonly used as a tool to augment the distribution of data points, however it normally does not have sufficient geometrical constraints due to: a) all geophysical inversion models being inherently non-unique; and b) the lack of knowledge of the physical property contrasts associated with specific lithologies. This contribution proposes the combined use of geophysical edge detection routines and 'three point' solutions from topographic data as a possible approach to obtaining geological contact geometry information (strike and dip), which can be used in the construction of a preliminary geological model. This derived geological information should first be assessed for its compatibility with the scale of the problem, and any directly observed geological data. Once verified it can be used to help constrain the preferred geological map interpretation being developed by the field geologist. The method models the contacts as planar surfaces. Therefore, it must be ensured that this assumption fits the scale and geometry of the problem. Two examples are shown from folded sequences at the Bathurst Mining Camp, New Brunswick, Canada.
Ham, Tae-Gew;Cho, Sam-Deok;Yang, Kee-Sok;Yoo, Seung-Kyong
Journal of the Korean Geosynthetics Society
/
v.7
no.3
/
pp.41-49
/
2008
This study was carried out the model experiment in laboratory to evaluate the bearing capacity improvement of soft ground as altered constraint condition of reinforcements according to geotextile, georid, steel bar. As a results, the value of BCR was increased linearly as improvement of the stiffness of reinforcements, and the factor governed the increasement of BCR was the increasement of frictions between reinforcement and clay as far as the constrain conditions increased until T=85.6kg. Moreover, An angle of inclination, ${\theta}$, between reinforcement and horizontal surface was distributed from $38^{\circ}$ to $50^{\circ}$ for Geotextile, from $45^{\circ}$ to $50^{\circ}$ for Geogrid and from $14^{\circ}$ to $16^{\circ}$ for steel bar. A radius of heaving, r, of clay ground by vertical weight at side was distributed from 0.6m to 0.7m for Geotextile, from 0.5m to 0.8m for Geogrid, and from 2.4m to 3.0m for steel bar. In case of steel bar, r was 4 times that of Geotextile.
Park, Jong-Ho;Trippe, Sascha;Krichbaum, Thomas;Kim, Jae-Young;Kino, Motoki;Bertarini, Alessandra;Bremer, Michael;de Vicente, Pablo
The Bulletin of The Korean Astronomical Society
/
v.40
no.1
/
pp.73.2-74
/
2015
The gas cloud G2 falling toward Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is supposed to provide valuable information on the physics of accretion flows and the environment of the black hole. We observed Sgr A* with four European stations of the Global Millimeter Very Long Baseline Interferometry Array (GMVA) at 86 GHz on 1 October 2013 when parts of G2 had already passed the pericenter. We searched for possible transient asymmetric structure - such as jets or winds from hot accretion flows - around Sgr A* caused by accretion of material from G2. The interferometric closure phases (which are zero if the spatial brightness distribution of the target is symmetric, and deviate from zero otherwise) remained zero within errors during the observation time. We thus conclude that Sgr A* did not show significant asymmetric (in the observer frame) outflows in late 2013. Using simulations, we constrain the size of the outflows that we could have missed to ${\approx}2.5$ mas along the major axis, ${\approx}0.4$ mas along the minor axis of the beam, corresponding to approximately 232 and 35 Schwarzschild radii, respectively; we thus probe spatial scales on which the jets of radio galaxies are suspected to convert magnetic into kinetic energy. As probably less than 0.2 Jy of the flux from Sgr A* can be attributed to accretion from G2, one finds an effective accretion rate ${\eta}M{\leq}1.5{\times}10^9kg/s{\approx}7.7{\times}10^{-9}M_{earth}/yr$ for material from G2. Exploiting the kinetic jet power-accretion power relation of radio galaxies, one finds that the rate of accretion of matter that ends up in jets is limited to $M{\leq}10^{17}kg/s{\approx}0.5M_{Earth}/yr$ less than about 20% of the mass of G2. Accordingly, G2 appears to be largely stable against loss of angular momentum and subsequent (partial) accretion at least on time scales ${\leq}1$ year.
Journal of the Institute of Electronics and Information Engineers
/
v.53
no.7
/
pp.27-38
/
2016
This work proposes a 12b 30MS/s 0.18um CMOS SAR ADC based on low-power composite switching with an active die area of $0.16mm^2$. The proposed composite switching employs the conventional $V_{CM}$-based switching and monotonic switching sequences while minimizing the switching power consumption of a DAC and the dynamic offset to constrain a linearity of the SAR ADC. Two equally-divided capacitors topology and the reference scaling are employed to implement the $V_{CM}$-based switching effectively and match an input signal range with a reference voltage range in the proposed C-R hybrid DAC. The techniques also simplify the overall circuits and reduce the total number of unit capacitors up to 64 in the fully differential version of the prototype 12b ADC. Meanwhile, the SAR logic block of the proposed SAR ADC employs a simple latch-type register rather than a D flip-flop-based register not only to improve the speed and stability of the SAR operation but also to reduce the area and power consumption by driving reference switches in the DAC directly without any decoder. The measured DNL and INL of the prototype ADC in a 0.18um CMOS are within 0.85LSB and 2.53LSB, respectively. The ADC shows a maximum SNDR of a 59.33dB and a maximum SFDR of 69.83dB at 30MS/s. The ADC consumes 2.25mW at a 1.8V supply voltage.
Journal of the Institute of Electronics Engineers of Korea TC
/
v.45
no.10
/
pp.17-28
/
2008
Rapid transmission of packets is important in mobile ad hoc networks. Therefore, a flooding algorithm which can guarantee a short delay is useful in various ways of packet transmission. Flooding algorithm is one of the packet transmission methods that broadcasts a packet to all nodes within a transmission range. It does not rebroadcast the same packet which is already received from other nodes. Basically, flooding algorithm's advantages are that it simply writes an address and a sequence number in a packet, and it can be adapted for topological changes easily. However, the basic flooding algorithm has a shortcoming that causes excessive traffic because all nodes transmit a packet at least once. To solve this problem, research about flooding algorithms that constrains duplicated transmission of packets based on probabilistic and geographical information is going on. However, the existing algorithm cannot guarantee short delay and low traffic. To reduce a delay, in this paper we propose a flooding scheme where a node which receives a broadcasted packet chooses and allocates a priority to one of its neighbor nodes and then the node transmits the packet promptly to the node to whom the priority was given. Moreover, we propose a totally fresh a roach to constrain duplicated transmission by searching a node that already received the same packet by using node's geographical position information. Lastly, we compare the performance of the proposed algorithm with the existing algorithm through simulation. The results show that the proposed algorithm can distribute packets through a lower number of total packet transmissions and faster delivery time than the existing algorithm.
D. W. KANG, J. S. CHOI, and G. R. TACK, A Study on Real-Time Sports Activity Classification & Monitoring Using a Tri-axial Accelerometer. Korean Jouranl of Sport Biomechanics, Vol. 18, No. 2, pp. 59-64, 2008. This study was conducted to study the real-time sports activity classification and monitoring using single waist mounted tri-axial accelerometer. This monitoring system detects events of sports activities such as walking, running, cycling, transitions between movements, resting and emergency event of falls. Accelerometer module was developed small and easily attachable on waist using wireless communication system which does not constrain sports activities. The sensor signal was transferred to PC and each movement pattern was classified using the developed algorithm in real-time environment. To evaluate proposed algorithm, experiment was performed with several sports activities such as walking, running, cycling movement for 100sec each and falls, transition movements(sit to stand, lie to stand, stand to sit, lie to sit, stand to lie and sit to lie) for 20 times each with 5 healthy subjects. The results showed that successful detection rate of the system for all activities was 95.4%. In this study, through sports activity monitoring. it was possible to classify accurate sports activities and to notify emergency event such as falls. For further study, the accurate energy consumption algorithm for each sports activity is under development.
This study pays attention to the assumption that the governance including the appointment of CEO is a key factor in the internal colonialism of local broadcasting. To evaluate the tendencies, it collects and analyzes the profile of CEOs, directors, and shareholders of the 17 regional affiliates of MBC and 9 local commercial broadcasting companies between the early and mid-1990s and 2015. It also discusses the local broadcasting personnel and its operations. By doing so, the study attempts to reveal how the internal colonialism of local broadcasting works. It finds out that the governance of regional broadcasters of MBC is controlled by the head office located in Seoul. At the same time, the governance of local commercial broadcasters is encroached by the tyrannical practices of major shareholders caused by the non-separation of ownership and management. These kinds of abnormal management of governance tend to constrain the investment on personnel and production. Finally, this study suggests some desirable directions of governance focusing on the appointment of CEO in terms of both legislative system and self-regulation. They include establishing a new proviso for programming protocols in local broadcasting, introducing a CEO & non-executive director nomination committee, and so forth.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.