• Journal of the Korean Mathematical Society
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• v.60 no.1
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• pp.115-141
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• 2023

We study a class of left-invariant pseudo-Riemannian Sasaki metrics on solvable Lie groups, which can be characterized by the property that the zero level set of the moment map relative to the action of some one-parameter subgroup {exp tX} is a normal nilpotent subgroup commuting with {exp tX}, and X is not lightlike. We characterize this geometry in terms of the Sasaki reduction and its pseudo-Kähler quotient under the action generated by the Reeb vector field. We classify pseudo-Riemannian Sasaki solvmanifolds of this type in dimension 5 and those of dimension 7 whose Kähler reduction in the above sense is abelian.

• Kyungpook Mathematical Journal
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• v.62 no.1
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• pp.43-55
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• 2022

Let R be a *-ring and n ≥ 1 be an integer. The objective of this paper is to introduce the notion of n-skew centralizing maps on *-rings, and investigate the impact of these maps. In particular, we describe the structure of prime rings with involution '*' such that _*[x, d(x)]_n ∈ Z(R) for all x ∈ R (for n = 1, 2), where d : R → R is a nonzero derivation of R. Among other related results, we also provide two examples to prove that the assumed restrictions on our main results are not superfluous.

• Kyungpook Mathematical Journal
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• v.62 no.1
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• pp.133-166
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• 2022

Let M be a semi-invariant submanifold with almost contact metric structure (𝜙, 𝜉, 𝜂, g) of codimension 3 in a complex space form M_n+1(c) for c ≠ 0. We denote by S and R_𝜉 be the Ricci tensor of M and the structure Jacobi operator in the direction of the structure vector 𝜉, respectively. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a certain scalar 𝜃 ≠ 2c and any vector fields X and Y on M. In this paper, we prove that if it satisfies R_𝜉𝜙 = 𝜙R_𝜉 and at the same time S𝜉 = g(S𝜉, 𝜉)𝜉, then M is a real hypersurface in M_n(c) (⊂ M_n+1(c)) provided that $\bar{r}-2(n-1)c{\leq}0$, where $\bar{r}$ denotes the scalar curvature of M.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.327-330
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• 2020

Port workers commuting by bicycle are threatened by damaged roads such as port halls created by large cargo. To solve this problem, a device was designed to detect broken roads with sensors and a camera.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.263-264
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• 2022

본 논문은 회사 직원들의 재택근무와 출퇴근 관리를 위한 Web 페이지이다. 프로젝트의 핵심 기능은 캘린더를 이용한 직원들의 출퇴근 관리로 근태, 재택, 휴가, 급여 관리 기능이 포함되어있다. 각 회사에서 이 프로그램을 이용할 시 직원들은 출근, 퇴근 버튼 기능으로 시간을 기록하고 휴가신청과 재택근무 일정을 확인할 수 있다. 관리자들은 직원들의 출퇴근 일정 목록과 재택일정, 휴가일정을 확인 가능하고 수정, 관리할 수 있다. 채팅 기능을 활용하여 직원과 관리자의 원활히 소통이 가능하다. 회사에서 필요한 근태 관리 시스템 기능들을 제공한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.481-483
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• 2023

본 논문에서는 어린이통학버스 안전사고 예방을 위한 지능형 탑승객 모니터링 시스템을 개발한다. 지능형 탑승객 모니터링은 통학버스 내 설치된 카메라로 부터 촬영되는 영상을 실시간으로 분석한 후 통학버스 내 발생할 수 있는 다양한 이벤트를 운전자 또는 교사에게 적시에 통보하여 잠재적 안전사고를 지능적으로 회피할 수 있도록 지원하는 시스템을 말한다. 제안한 시스템은 Yolov4, DeepSort, MediaPipe등의 인공지능 관련 SW기술을 활용하여 영상을 분석한 후 싸움과 같은 이상행동, 정차 후 잔류 인원 발생, 하차자와 차량 간의 안전거리 확보 여부를 포함하는 3가지 이벤트를 인식한 후 운전자 또는 교사에게 알림을 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.854-855
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• 2023

안전벨트 미착용 혹은 통학 차량 미하차로 인한 사고를 방지하기 위해 좌석에 압력 센서와 안전벨트에 센서를 부착하여 착석하지 않은 상태, 안전 벨트 미착용, 안전 벨트 착용으로 3단계로 나누어 탑승자의 상태 정보를 운전석에 위치한 디스플레이에 정보를 표시하여 안전 사고가 발생할 가능성을 줄이고자 한다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1287-1292
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• 2007

The purpose of this study was to compare knowledge on hypertension and blood parameters through blood pressure control of hypertensive patients commuting to a public health center. Hypertensive subjects were classified according to their blood pressures into a well-controlled group (SBP<140 mmHg and DBP<90 mmHg, n=44) and an uncontrolled group ($SBP\geq140mmHg\;or\;DBP\geq90mmHg$, n=41). All subjects were interviewed for clinical characteristics, effort for health maintenance and knowledge on hypertension and nutrition. Biochemical measurement of blood urea nitrogen, creatinine, triglyceride, total cholesterol, HDL-cholesterol and fasting blood glucose (FBG) were obtained from subjects. The knowledge about hypertension and effort for health maintenance were not significantly different between the groups. However, the nutrition knowledge score of the well-controlled group was significantly higher (p<0.05) than that of the uncontrolled group. On the test of nutrition knowledge, 97.7% of the well-controlled group answered correctly to the item, 'Medication is an easy way to control blood pressure'. This result was significantly higher (p<0.05) than that of the uncontrolled group of whom 82.9% answered correctly. Participants in both groups had only a little understanding about the importance of a balanced diet. Blood parameters were in the normal range and there was not a significant difference between the groups. However total cholesterol, triglyceride and fasting blood glucose levels of the uncontrolled group were higher than those of the well-controlled group. Therefore, education programs about the continuous control of hypertension through careful monitoring, medication, and exercise are required. The uncontrolled group was especially in need of strengthening education. Also more effective nutrition education programs about low salt, high fiber, low cholesterol, and balanced diets are required for hypertensive patients commuting to public health center.

• Journal of dental hygiene science
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• v.6 no.1
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• pp.11-17
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• 2006

The purpose of this study was to help prevent the turnover of competent dental hygienists in a bid to boost the efficiency of personnel management for dental health care workers and provide higher-quality oral health services. After relevant literature and data were reviewed, a survey was conducted on dental hygienists, who worked at dental institutes, for approximately four months from September to December 2004 to identify what affected their turnover. The findings of the study were as below: 1. Regarding turnover experience, 39.7 percent of the dental hygienists investigated had such an experience. As to turnover frequency, those who took up another employment once made up the largest group(28.2%), followed by twice(8.0%) and three times(2.9%). The most dominant turnover reason was working conditions(66.7%), followed by seeking being hired by larger institutes(36.2%), pay(21.7%), relationship with dentists(11.6%) and commuting distance(11.6%). 2. As for their hope for turnover, 82.8 percent hoped to take up another employment, and working conditions were cited as the most common reason(44.4%), followed by pay(33.3%), commuting distance(18.1%), marriage(13.2%), health/use of leisure time(11.8%), and commuting time(10.4%). 3. Concerning preference for future workplace, 38.5 percent, the largest group, wanted to work at public health clinics. As to a preferred term of working as dental hygienists, 50.0 percent, the greatest group, hoped to serve as dental hygienists until they are financially secure. 34.5 percent, the second largest group, intended to keep working until they reach the age limit. In regard to their responsibility for family economy, 47.7 percent, the greatest percentage, shouldered the partial responsibility for that, and 31.6 percent assumed no responsibility. 4. As to their intention to quit working as dental hygienists, 61.5 percent were willing to do that, and marriage(29.0%) was singled out as the most frequent reason, followed by working conditions(27.1%), child birth(22.4%), health/housework(18.7%), pay(15.9%) and learning/use of free time(15.0%).

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.97-108
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• 2008

Like always selecting anything in everyday lives, We must choose a travel mode to achieve its purposes driven by diverse factors such as travel distance and accessibility of public transit. Assuming that they are differentiated depending on whether a travel purpose is commuting, shopping or leasure, the study investigated their distinguished impacts on travel mode choice by using binary logit models by travel purpose and mode. Identifying that travel time has an important role in choosing a travel mode whether its purpose is any, the results show that longer travel time tends to increase the possibilities of taking public transit, transfer and rail transit rather than bus. In addition, the easy use of a car and its parking to travelers is more important in their choosing an automobile as a travel mode than other factors. In the models of identifying the probability of mode choice between bus and rail transit, we find that its choice tends to be decided by travelers depending on whether any public transit mode is more accessible to them. When comparing the results among travel purposes, we identify that the easy use of a car and parking in their destination is more important for commuting, while accessibility of public transit in their origination increases the probability of taking a transit mode.