• Journal of Communications and Networks
• /
• v.9 no.2
• /
• pp.198-209
• /
• 2007

This paper provides a thorough study on shared segment protection (SSP) for mesh communication networks in the complete routing information scenario, where the integer linear program (ILP) in [1] is extended such that the following two constraints are well addressed: (a) The restoration time constraint for each connection request, and (b) the switching/merging capacity constraint at each node. A novel approach, called SSP algorithm, is developed to reduce the extremely high computation complexity in solving the ILP formulation. Basically, our approach is to derive a good approximation on the parameters in the ILP by referring to the result of solving the corresponding shared path protection (SPP) problem. Thus, the design space can be significantly reduced by eliminating some edges in the graphs. We will show in the simulation that with our approach, the optimality can be achieved in most of the cases. To verify the proposed formulation and investigate the performance impairment in terms of average cost and success rate by the additional two constraints, extensive simulation work has been conducted on three network topologies, in which SPP and shared link protection (SLP) are implemented for comparison. We will demonstrate that the proposed SSP algorithm can effectively and efficiently solve the survivable routing problem with constraints on restoration time and switching/merging capability of each node. The comparison among the three protection types further verifies that SSP can yield significant advantages over SPP and SLP without taking much computation time.

• The Journal of Korean Society for School & Community Health Education
• /
• v.18 no.3
• /
• pp.83-95
• /
• 2017

Objectives: The purpose of the research is understand the priorities of national competency standards vocational key competence factors in nurse who is work in Seoul and Incheon. Methods: The design of this study is descriptive investigation research, and the subjects were 144 nurse. we establish the vocational key competency defined in national competency standards as analytic hierarchy analysis model. The vocational key competency has 10 categories and 34 sub-categories. And based on the survey in nurse, the weight representing relative importance of each factor were calculated by using analytic hierarchy process method. Results: The analytic hierarchy process analysis on 10 categories showed that professional ethics(0.149) was higher than any other categories while that of numeracy(0.040) was at the bottom. And the analysis on sub-categories revealed that the most important factors in each categories included the Ethical community(Professional ethics), Conflict management skills(Interpersonal skills), Problem solving capability(Problem-solving skills), Listening skills(Communication skills), Applicable technical skills(Technical skills), Ability to understand business(Ability to understand organizational structures), Information processing capabilities(Information capacity), Self-management skills(Self-development capability), Ability to manage time(Resource management capabilities), Basic math skills(Numeracy). Conclusions: The results in this study can be used as basic data for the development of liberal arts curriculum for Nursing.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.4
• /
• pp.217-224
• /
• 2022

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

• Journal of The Korean Association For Science Education
• /
• v.12 no.3
• /
• pp.49-59
• /
• 1992

New-Piagetian theory has proposed that mental capacity and mental demand do a critical role in human cognitive processes. In this study, the students' mental capacity and the mental demand of the given problems were examined. The principal findings of the study are as follows; (1) There was no significant difference among achievement scores of subjects (3rd grade students of middle school, 2nd grade students of high school, 3rd grade students of high school) in the items of balance that needed specific content knowledge. But, in the Newton's 2nd law items that needed specific content knowledge, there was significant difference be ween3rd grade students of middle school and high school students(2nd, 3rd). According to increase of mental demand, middle school students' achievement score appeared to decrease linearly. However high school students' achievement score didn't change untill they faced the items of critical mental demand. When mental demand was beyond critical mental demand,their score was decreased rapidly. (2) According to hierchical analysis of items, the more mental demand an item needed, the higher or at least the same hierachical item was. These results showed that mental demand was the main factor which decided diffculties of problem solving (3) It was possible for students to solve the newton's 2nd law item that had one or two more mental demand relative to balance beam item. Although the item needed the same mental demand.students recognized that the Newton's 2nd law items were easier than the balance beam items.

• Communications of Mathematical Education
• /
• v.24 no.3
• /
• pp.525-541
• /
• 2010

The purpose of this thesis is to investigate the effects of the topics in basic mathematics on academic achievement in order to improve the problem-solving abilities of low achievement students in university general mathematics. This program has been conducted from P University as a part of Education Capacity Enhancing Project. The goals of this program are to make students who have fear to mathematics feel confident for mathematics, and make easier to study general mathematics and major field without any difficulties for the students. The topics in basic mathematics was enforced with solving problem based on comprehension of the basic concept and computer-based learning. The classes were organized as Algebra-Geometry, Calculus, and General mathematics class by students' applications for classes and basic academic ability. As a result, the topics in basic mathematics has been evaluated as positive way to effect satisfaction and learning effect for the students who have low-level in basic academic ability. And also, according to the survey, the result shows that assignment through Webwork system and Mathematica program practice are helpful for learning basic mathematics. But several measures are asked for participation in the class and prevention for quitter of participants.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.353-362
• /
• 2020

This was a single group pretest-protest pre-experimental study designed to find out whether writing using media enhances creative convergence capacity. Data were collected from 30 C university students in C city, from March 1st to July 15th, 2020. Analysis was done using IBM SPSS 25.0 for frequency, percentage, average, standard deviation, and paired t-test. Creative problem solving ability was enhanced by an average of 0,63 points (p<.001), critical thinking tendency by 1.06 points (p<.001), self-leadership by 0,53 points (p<.001), and self-control by an average of 0.51 points, so was statistically significant (p=.001). Writing using media had the effect of improving creativity and integration capabilities. The results of this study are expected to be used as basic data for the development of educational programs for creativity and integration enhancement at university-level. Also, follow-up studies on the effectiveness of writing education by utilizing web media as text and tools simultaneously and customized university-level writing education utilizing media are required.

• Industrial Engineering and Management Systems
• /
• v.7 no.2
• /
• pp.126-132
• /
• 2008

The bin packing problem (BPP) is an NP-Complete Problem. The problem can be described as there are $N=\{1,2,{\cdots},n\}$ which is a set of item indices and $L=\{s1,s2,{\cdots},sn\}$ be a set of item sizes sj, where $0<sj{\leq}1$, ${\forall}j{\in}N$. The objective is to minimize the number of bins used for packing items in N into a bin such that the total size of items in a bin does not exceed the bin capacity. Assume that the bins have capacity equal to one. In the past, many researchers put on effort to find the heuristic algorithms instead of solving the problem to optimality. Then, the quality of solution may be measured by the asymptotic worst-case ratio or the average-case ratio. The First Fit Decreasing (FFD) is one of the algorithms that its asymptotic worst-case ratio equals to 11/9. Many researchers prove the asymptotic worst-case ratio by using the weighting function and the proof is in a lengthy format. In this study, we found an easier way to prove that the asymptotic worst-case ratio of the First Fit Decreasing (FFD) is not more than 11/9. The proof comes from two ideas which are the occupied space in a bin is more than the size of the item and the occupied space in the optimal solution is less than occupied space in the FFD solution. The occupied space is later called the weighting function. The objective is to determine the maximum occupied space of the heuristics by using integer programming. The maximum value is the key to the asymptotic worst-case ratio.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.23 no.2
• /
• pp.29-46
• /
• 1998

In this paper, we develop detailed algorithms for implementing the so-called Limited Column Generation procedure for Local Access Telecommunication Network(LATN) design problem. We formulate the problem into a tree-partitioning problem with an exponential number of variables. Its linear programming relaxation has all integral vertices, and can be solved by the Limited Column Generation procedure in just n pivots, where n is the number of nodes in the network. Prior to each pivot. an entering variable is selected by detecting the Locally Most Violated(LMV) reduced cost, which can be obtained by solving a subproblem in pseudo-polynomial time. A critical step in the Limited Column Generation is to find all the LMV reduced costs. As dual variables are updated at each pivot, the reduced costs have to be computed in an on-line fashion. An efficient implementation is developed to execute such a task so that the LATN design problem can be solved in O(n$^2$H), where H is the maximum concentrator capacity. Our computational experiments indicate that our algorithm delivers an outstanding performance. For instance, the LATN design problem with n＝150 and H＝1000 can be solved in approximately 67 seconds on a SUN SPARC 1000 workstation.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1995.04a
• /
• pp.54-68
• /
• 1995

In this paper, we develop detailed algorithms for implementing the so-called Limited Column Generation procedure for Local Access Telecommunication Network (LATN) Design problem. We formulate the problem into a tree-partitioning problem with an exponential number of variables. Its linear programming relaxation has all integral vertices, and can be solved by the Limited Column. Generation procedure in just n pivots, where n is the number of nodes in the network. Prior to each pivot, an entering variable is selected by detecting the Locally Most Violated (LMV) reduced cost, which can be obtained by solving a subproblem in pseudo-polynomial time. A critical step in the Limited Column Generation is to find all the LMV reduced costs. As dual variables are updated at each pivot, the reduced costs have to be computed in an on-line fashion. An efficient implementation is developed to execute such a task so that the LATN Design problem can be solved in O(n$^{2}$H), where H is the maximum concentrator capacity. Our computational experiments indicate that our algorithm delivers an outstanding performance. For instance, the LATN Design problem with n = 150 and H = 1000 can be solved in approximately 67 seconds on a SUN SPARC 1000 workstation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.12
• /
• pp.177-183
• /
• 2010

Overhead transmission lines in domestic area have been built by several different design standards of dip and ground clearance. This paper describes an experimental study for evaluating load capacity and dip margin in overhead transmission lines. Such design standards for selection of overhead transmission conductors, dip and ground clearance, as well as electrical equipment technical standard are discussed. Based on daily load and weather data, several characteristics such as line utilization factor, load factor, conductor temperature and dip, etc. are analyzed, and compared with the specified levels of design standards. As a result, it is verified that DLR method can be a clue of the solving of the problem, for occurring in old transmission conductors which may be rarely operating below standards.