• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.103-113
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• 2012

The ButterStar Observatory at the Dongducheon High School has been working for photographic observations of the Sun since October 16, 2002. In this study, we observed the Sun at the ButterStar observatory for 3,364 days from October 16, 2002 to December 31, 2011, and analyzed the photographic sunspot data obtained in 1,965 days. The correction factor $K_b$ for the entire observing period is 0.9519, which is calculated using the linear least square method to the relationship between the daily sunspot number, $R_B$, and the daily international relative sunspot number, $R_i$. The yearly correction factor calculated for each year varies slightly from year to year and shows a trend to change along the solar cycle. The correction factor is larger during the solar maxima and smaller during the solar minima in general. This implies that the discrepancy between a relative sunspot number, R, and the daily international relative sunspot number, $R_i$, can be reduced by using a yearly correction factor. From 2002 to 2008 in solar cycle 23, 35.4% and 64.6% of sunspot groups and 35.1% and 64.9% of isolated sunspots in average occurred in the northern hemisphere and in the southern hemisphere, respectively, and from 2008 to 2011 in solar cycle 24, 61.3% and 38.7% of sunspot groups and 65.0% and 35.0% of isolated sunspots were observed, respectively. This result shows that the occurrence frequency for each type of sunspot group changes along the solar cycle development, which can be interpreted as the emerging and decaying process of sunspot groups is different depending on the phase of solar cycle. Therefore, it is considered that a following study would contribute to the efforts to understand the dependence of the dynamo mechanism on the phase of solar cycle.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.222-226
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• 2013

Objectives: The aim of this study was to assess the influence of operator experience level on the lifespan of the WaveOne Primary file (Dentsply Maillefer, Ballaigues, Switzerland) in extracted teeth. Materials and Methods: Moderately curved canals of extracted maxillary and mandibular molars were randomly distributed into 2 groups: experienced and inexperienced operators. Ten files were allocated to each group (n = 10). Each canal was prepared until the working length was reached, and the same file was used to prepare additional canals until it separated. The number of canals prepared before file separation was recorded. The fragment length of each file was measured, and the location of the fragment in the canal was determined. Data were statistically analysed using the independent 2-sample t-test. Results: The 2 operators prepared a total of 324 moderately curved canals of maxillary and mandibular molars. There was no significant intergroup difference in the mean number of canals prepared (p = 0.27). The average lifespan of the WaveOne Primary file was 17.1 and 15.3 canals, and the longest lifespan was 25 and 20 canals, when used by experienced and inexperienced operators, respectively. There were no statistically significant intergroup differences in separated fragment length and location. Conclusions: Within the limitations of this study, operator experience level appears to have no effect on the lifespan of the WaveOne Primary file in preparation of moderately curved canals. Single teeth with multiple canals can be prepared safely even by a novice operator by using a single file.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.70-78
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• 2002

Advanced safety vehicle (ASV) equipped with intelligent drivers advisory functions for controlling vehicle to follow the lead vehicle and/or warning drivers on forward traffic impediments according to the roadway and traffic circumstances has been recently developed and on the market internationally. Standardization processes for ASV system functions have been issued in IS0/TC204 Working Group 14 (Vehicle/Roadway Warning and Control System) since 1995. Research projects developing test and evaluation technologies for ASV in establishing safety standards and/or conformity related to the national roadway and traffic circumstances are under study internationally. In Korea, an integrated test and evaluation Program was developed for the assessment of adaptive cruise control (ACC) system under the ITS research and development projects funded by the Ministry of Construction and Transportation (MOCT). This paper demonstrates the integrated test and evaluation Programs for ACC system based on the draft international standard with related to the domestic roadway and traffic conditions. Field tests fulfilled under the scenarios based on the integrated test & evaluation programs for ACC system are discussed along with a review of earlier research work regarding international standards and the safety regulations.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.123-132
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• 2016

This study starts from the research question that "Why some companies decide to keep working in partnership even when they are not satisfied with the partner companies simply because they are old business partners." The authors try to find the answer in terms of customer value considering the phases of B2B transaction spectrum: transaction value, relationship value and appraisal value implementing empirical research. The result shows that the intension to retain the relation with an existing partner is formed by the trade-off between the benefit and cost of both contract value and relationship value and not the sole value was dominant. The unique point of the study is that current study is considering these two factors as dependent variables which affect the relationship continuity which is not the case in existing researches.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.1
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• pp.7-17
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• 1998

Since patients who have suffered from strokes have chronic health problems, the development of a protocol for home care nursing is required. Therefore, this study was done to test the effects of such a protocol on stroke patients. This study was conducted by using a single group pre-post design. The subjects for the study were 13 home care nurses and 30 home care patients who had a stroke. Data collection was done from October 1997 to February 1998. The collected data was analyzed using the Wilcoxon signed rank test and paired t-test and the results were as follows : 1. The first hypothesis that 'working satisfaction of home nurses would be higher after using the home care protocol' was supported. 2. The second hypothesis that 'patients' satisfaction would be higher after using the home care protocol' was rejected. 3. The third hypothesis that 'the level of ADL of patients would be higher after using the home care protocol' was supported. In conclusion, by using a home care protocol, the satisfaction of nurses' work and the ADL of patients increased, and the patients' satisfaction also increased without statistical significance. The above results confirm that the application of a home care protocol is very effective. Thus, this protocol can be helpful in the quality care of stroke patients. Therefore, developing and organizing protocols, according to health problem, can be useful for beginner nurses who interact with high risk patients.

• Korean Journal of Community Nutrition
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• v.4 no.4
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• pp.575-586
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• 1999

We studied teachers' breakfast habits and their preferences on various breakfast types so that we will furnish data to nutrition education including ideal breakfast habit and development of various menus. The meal considered as most importantly were dinner (66.2%), fellowed by lunch(21.6%), all three meals(6.4%) and breakfast(5.8%). Men considered breakfast more importantly than women. On the contrary, women considered dinner more significantly compared to men. The group aged 45 and over emphasized breakfast and all three meal. 78.1% of subjects answered that breakfast is necessary and 61.5% of subjects ate breakfast regularly. Those who have breakfast regularly was lower in women(50.0%) than in men(71.3%). Instead, those who eat breakfast irregularly or skipping it was higher among women(50.0%) than among men(29.7%). The percentages of having breakfast regularly was higher in older groups. For breakfast, 82.1% of subjects had conventional meal which included rice, soup and Kimch. On the other hand, 13.9% of subjects had Western style breakfast such as bread, cornflakes and milk. The major reason for eating breakfast regularly was answered as 'maintain health(71.8%)'. The major reason for eating breakfast irregularly or skipping was 'don't have enough time to eat(48.0%)', 'poor appetite(28.6%)'. The major physical discomfort after skipping breakfast was 'experience brash(35.6%)', 'lack of physical strength(35.1%)'. Subjects answered that breakfast served as 'source of physical strength(64.9%)', 'provides nutritional balance for a day(21.1%)' and 15.0% of subjects ate out breakfast. Therefore, it is suggested that teachers as well as school children be provided breakfast and snack in school. The preference and opinion regarding breakfast types wer conventional food including rice, soup and Kimch(67.0%). There was a little preference in Western style food such as bread, milk and coffee(14.3%), cereals mixture and porridge(10.7%). It was noticeable that 49.1% of females and those who reside in Seoul(42.2%) selected various breakfast types excluding conventional food. Therefore it will be accepted to working women as breakfast if it is nutritionally balanced and cook well in short time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.224-227
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• 2016

This paper proposes a design of W-band mm-wave wideband monopulse comparator using waveguide structure for applications. The main idea of proposed design is to combine a self-compensating phase shifter on $90^{\circ}$ hybrid for wideband $180^{\circ}$ hybrid. Using multiple conventional phase shifters, because of their narrow-band characteristics, tends to restrict working bandwidth of system including antennas. Proposed comparator could relieve the problem since it applies the self-compensating phase shifter. The comparator has waveguide structure so it shows excellent characteristic in loss. It also show wideband characteristic in amplitude and phase response between ports.

• Human Ecology Research
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• v.55 no.4
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• pp.441-450
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• 2017

Childcare related studies have focused on the characteristics of care work, policy aspects, user family satisfaction, and job satisfaction of childcare helpers. But there have been few studies on family system characteristics that support childcare givers. Thus, this study conducted on the topic, "How to characterize the family resilience of long-term childcare givers?" The subjects belong to a healthy family support center in U. City, who belong to a group with an income in the top 20 % of about 20 persons working for more than 3 years. In an interview, qualitative questions were used Walsh's family resilience. The results are as follows. First, they had economic hardship, but their family would stand together and build up a family's power based on the couple's faith. They had a family role model based on their parents' family that included inherited maternity qualities from their mother. Second, the flexibility of the family organization changed to autonomous or co-role type and the connectivity. Especially, they appear as a family's leader. Third, their family communication was active, shared-care, responsible and passionate with family affection and understanding. The conclusions results are as follows. Participants were high school graduates as well as had work experience. They were characterized by positive family energy, a family belief system, family-based resources, flexibility, connectivity, open family communication and expression skills. Therefore, it can be suggested that it is necessary to check the family's resilience during an interview for the reliable, long-term supply of human resources for childcare activities.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.113-120
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• 2006

A node of mobile IPv6 moving foreign networks needs authentication process to support right services against from security threat. AAA is a trust infrastructure that authenticates, authorizes, and accounts nodes receiving a network service. And Mobile IPv6 Working Group recommends use of AAA infrastructure to authenticate mobile nodes. Event though AAA infrastructure provides strong authentication functions, it should exchange a lot of messages to authenticate mobile nodes every movement. The exchange of lots of messages causes latency and it is interfered with realization of real-time communication. This paper proposes an authentication method of improved speed using hash value of mobile node to reduce authentication latency. Directly after movement, a mobile node applying a Proposed method uses extended existing security authentication for a while and deletes the establishment latency of new security authentication. Performance evaluation of a proposed method verifies the efficiency through the analysis of cost comparison with other methods. The conclusion of performance evaluation is that the proposed method gets more 25% performance improvement than a general method when a mobile node moves another subnet.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.121-128
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• 2006

In Mobile IPv6, a handover latency is an important issue. To reduce the handover latency, mipshop working group in IETF has studied the fast handover(FMIPv6) which creates and verifies a new care-of address(NCoA) in advance before a layer 2 handover resulting in reduced handover latency. Even in FMIPv6, the NCoA must be registered in a home agent(HA). This registration still creates a significant amount of delay. To reduce registration latency, we propose a tentative and early binding update(TEBU) scheme that the NCoA is registered in the HA in advance during the layer 2 handover based on FMIPv6. We use cost analysis for the performance evaluation. As a result, we found that the TEBU scheme guarantees lower handover latency than FMIPv6 as much as approximately 21%.