• Journal of applied mathematics & informatics
• /
• 제16권1_2호
• /
• pp.251-263
• /
• 2004

In this paper, algorithms for computing the minimal polynomial and the common minimal polynomial of resultant matrices over any field are presented by means of the approach for the Grobner basis of the ideal in the polynomial ring, respectively, and two algorithms for finding the inverses of such matrices are also presented. Finally, an algorithm for the inverse of partitioned matrix with resultant blocks over any field is given, which can be realized by CoCoA 4.0, an algebraic system over the field of rational numbers or the field of residue classes of modulo prime number. We get examples showing the effectiveness of the algorithms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제48권2호
• /
• pp.71-78
• /
• 2022

This study was conducted to review the efficacy of different sources of stem cells in bone regeneration of cleft palate patients. The majority of previous studies focused on the transplantation of bone marrow mesenchymal stem cells. However, other sources of stem cells have also gained considerable attention, and dental stem cells have shown especially favorable outcomes. Additionally, approaches that apply the co-culture and co-transplantation of stem cells have shown promising results. The use of different types of stem cells, based on their accessibility and efficacy in bone regeneration, is a promising method in cleft palate bone regeneration. In this regard, dental stem cells may be an ideal choice due to their efficacy and accessibility. In conclusion, stem cells, despite the lengthy procedures required for culture and preparation, are a suitable alternative to conventional bone grafting techniques.

• 한국지역지리학회지
• /
• 제18권1호
• /
• pp.1-16
• /
• 2012

생태관광 위주의 관광객이 빠르게 증가하면서 관광지에 대한 구체적인 정보에 대한 수요 역시 급증하고 있다. 탐방객을 대상으로 한 설문조사 결과 생태관광 자원 중에서는 역사나 문화보다는 자연생태 자원에 많은 관심을 가지고 있으며, 현재 부족하거나 보완되어야 할 내용으로는 지역에 대한 정보를 꼽고 있었다. 본 논문에서는 관광객들에게 정확하고 상세하고 표준화된 정보를 제공하기 위해 생태관광자원을 수요자 입장에서의 관광객의 활동 성격에 따른 분류와 생태자원에 의한 분류로 대분하였다. 그리고 다시 활동 성격에 따른 분류는 자연형, 교육형, 소통형, 모험형의 4가지 유형으로 세분하였다. 또한 이에 맞는 웹 기반의 홈페이지를 개발한 후 태안과 울릉도의 사례를 제시하였다. 향후 시범 운영을 통해 드러난 문제점을 보완한다면, 생태관광 분야에 있어서 모바일 기반의 디지털 스토리텔링 기술 표준을 제시할 수 있을 것으로 기대한다.

• International Journal of Automotive Technology
• /
• 제7권7호
• /
• pp.785-793
• /
• 2006

The topic of this study is the control strategy of a mild hybrid electric vehicle (HEV) equipped with a continuously variable transmission (CVT). A brief powertrain and vehicle configuration is introduced followed by the control strategy of the HEV with emphasis on two key parts. One of them is an ideal operating surface (IOS) that operates the CVT powertrain optimally from the viewpoint of the tank-to-wheel efficiency. The other is a charge sustaining energy management to maintain the battery state of charge (SOC) within an appropriate level. The fuel economy simulation results of the HEV over standard driving cycles were compared with those of the baseline vehicle. Depending on the driving cycle, 1.3-20% fuel saving potential is predicted by the mild hybridisation using an integrated starter alternator (ISA). The detailed energy flow analysis shows that the majority of the improvement comes from the idle stop function and the benefits for electrical accessories. Additionally, the differences between the initial and the final SOC are in the range $-1.0{\sim}+3.8%$ in the examined cycle.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권5호
• /
• pp.1654-1675
• /
• 2014

In practical wireless systems, the erroneous channel state information (CSI) sometimes deteriorates the performance drastically. This paper focuses on robust design of coordinated set planning of coordinated multi-point (CoMP) transmission, with respect to the feedback delay and link error. The non-ideal channel models involving various uncertainty conditions are given. After defining a penalty factor, the robust net ergodic capacity optimization problem is derived, whose variables to be optimized are the number of coordinated base stations (BSs) and the divided area's radius. By the maximum minimum criterion, upper and lower bounds of the robust capacity are investigated. A practical scheme is proposed to determine the optimal number of cooperative BSs. The simulation results indicate that the robust design based on maxmin principle is better than other precoding schemes. The gap between two bounds gets smaller as transmission power increases. Besides, as the large scale fading is higher or the channel is less reliable, the number of the cooperated BSs shall be greater.

• 한국식품과학회지
• /
• 제22권5호
• /
• pp.575-581
• /
• 1990

일정한 열처리 공정에 대해 Equivalent point가 존재함을 이상적인 두가지의 직접가열곡선 즉, $120^{\circ}C$에서 10분간 $135^{\circ}C$에서 10초간의 등온가열 곡선을 이용하여 예시하였다. 이러한 조건하에서 Arrhe nius model을 적용한 경우 임의의 Ea-값을 사용하여 G-값을 결정하고 Bigelow model을 적용한 경우, 임의의 z-값을 사용하여 F-값을 결정하였다. 이들 값을 사용하여 Equivalent time과 Equivalent Temperature를 두가지 방법 즉, 직교좌표법과 회기분석법에 의해 결정하였다. 이들 두 방법에 의해 결정된 Equivalent Point는 서로 일치하였으며 각각의 값은 초기에 가정했던 직접가열곡선의 가열시간 및 온도와 일치하였다.

• Radiation Oncology Journal
• /
• 제2권1호
• /
• pp.149-153
• /
• 1984

Postoperative radiotherapy of breast cancer makes it possible to reduce loco-regional recurrence of breast cancer. The treatment technique, which can reduce the low-dose region at the junction and lung, is required. To produce proper dose distribution of internal mammary chain and chest wall, authors tried to find the method to expose $^{60}Co\;\gamma-ray$ on internal mammary region and 7MeV electron on chest wall. Exposure time of $^{60}Co\;\gamma$ and monitor unit of 9MeV were selected so that dose of $^{60}Co$ at 4cm depth was the same as that of 7Mev electron at $80\%$ dose depth. The position and direction of electron beam were changed for $^{60}Co$ beam: $0^{\circ},\;5^{\circ}$ for 0cm seperation; $0^{\circ},\;5^{\circ},\;10^{\circ}$ for 0.5cm seperation; $5^{\circ},\;10^{\circ},\;15^{\circ}$ for 1cm seperation. The results are as followings. 1. When the seperation of two fields was increased, dose on the axis of $^{60}Co$ beam was increased and dose at the junction region decreased while the volume of lung to be exposed to high dose and hot spot size were irregularly changed. 2. The dose distribution in the target volume of internal mammary and chest wall was most ideal when the seperation of two fields was $0\~0.5cm$ and the direction of electron beam was parallel to $^{60}Co$ beam.

• 한국해양환경ㆍ에너지학회지
• /
• 제11권4호
• /
• pp.181-190
• /
• 2008

기후변화 및 교토의정서상의 온실가스 의무감축요구에 대응하기 위하여 발전소 및 제철소 등 대규모 발생원에서부터 포집한 $CO_2$를 파이프라인이나 선박 등을 통해 수송하고, 이를 해저 지질구조내 대규모로 수백-수천년 이상 장기간 저장 및 관리하는 $CO_2$ 해양지중저장기술이 국내외적으로 주목 받고 있다. $CO_2$ 해양지중저장 처리 시스템 설계를 수행하는데 있어 전산모사를 통한 공정 설계는 필수적이다. 즉, 수치 모델링을 통하여 $CO_2$ 해양지중저장 처리에 필요한 일련의 공정을 열역학 상태방정식 등을 이용하여 모사하는 것이다. 본 논문에서는 $CO_2$ 해양지중저장 처리를 위한 공정 설계에 사용되는 열역학 상태방정식들을 비교 분석하였다. 또한, 상태방정식 계산결과의 정확성을 평가하기 위하여 실험으로부터 구해진 데이터와 비교를 수행하였다. 이상기체 상태방정식과 SRK식은 $29.85^{\circ}C$, 60 bar 이상에서 밀도를 전혀 예측하지 못하였으며, 고온 고압의 초임계 상태에서 100% 내외의 오차를 보였다. BWRS 식은 임계온도 근처인 $29.55^{\circ}C$, 임계압력 근처인 $60{\sim}80\;bar$ 사이의 영역에서 실험값을 전혀 예측하지 못하고 최대 100%의 차이를 보였다. $CO_2$ 해양지중저장 처리의 저장지 조건인 온도 $31.1^{\circ}C$ 이상, 압력 73.9 bar 이상의 초임계 상태에서 PR 식과 PRBM 식은 실험값을 비교적 잘 예측하였다. 따라서 $CO_2$ 해양지중저장처리 공정 중 고온, 고압 영역에서는 상기 상태방정식을 이용한 공정 설계가 유용하다고 판단된다.

• 한국작물학회지
• /
• 제45권1호
• /
• pp.59-70
• /
• 2000

In nature, plant diseases, insects and parasites (hereafter called as "pest") must be co-survived. The most common expression of co-survival of a host crop to the pest can be tolerance. With tolerance, chemical uses can be minimized and it protects environment and sustains host productivity and the minimum pest survival. Tolerance can be applicable in all living organisms including crop plants, lifestocks and even human beings. Tolerant system controls pest about 90 to 95% (this pest control system often be called as horizontal or partial resistance), while the use of chemicals or selection of high resistance controls pest 100% (the most expression of this control system is vertical resistance or true resistance). Controlling or eliminating the pests by either chemicals or vertical resistance create new problems in nature and destroy the co-survial balance of pest and host. Controlling pests through tolerance can only permit co-survive of pests and hosts. Tolerance is durable and environmentally-friend. Crop cultivars based on tolerance system are different from those developed by genetically modified organism (GMO) system. The former stabilizes genetic balance of a pest and a host crop in nature while the latter destabilizes the genetic balance due to 100% control. For three decades, the author has implemented the tolerance system in breeding maize cultivars against various pests in both tropical and temperate environments. Parasitic weed Striga species known as the greatest biological problem in agriculture has even been controlled through this system. The final effect of the tolerance can be an integrated genetic pest management (IGPM) without any chemical uses and it makes co-survival of pests in nature.in nature.

• 한국전기전자재료학회논문지
• /
• 제32권4호
• /
• pp.276-280
• /
• 2019

In this study, we investigated the crystal defects and grain boundary properties in a ZZCCC ($ZnO-Zn_2BiVO_6-Co_3O_4-Cr_2O_3-CaCO_3$) varistor, with the liquid-phase sintering aid $Zn_2BiVO_6$ developed by our laboratory. The ZZCCC varistor sintered at $1,200^{\circ}C$ exhibited excellent nonlinear current-voltage characteristics (${\alpha}=63$), with oxygen vacancy ($V_o^*$ ; 0.35 eV) as a main defect, and an apparent activation energy of 1.1 eV with an electrically single grain boundary. Therefore, among the various additives to improve the electrical properties of ZnO varistors, if $Zn_2BiVO_6$ is used as a liquid phase sintering aid, it will be ideal to use Co for the oxygen vacancy and Ca for the electrically single grain boundary. This will allow the good properties of ZnO varistors to be maintained up to high sintering temperatures.