• Journal of KIISE:Computer Systems and Theory
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• v.33 no.12
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• pp.880-884
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• 2006

In an edge-weighted(positive, negative, or zero weights are possible) tree, we want to solve the problem of finding a longest path such that the sum of the weights of the edges in tile path is non-negative. To find a longest non-negative path of a tree we present a sequential algorithm with O(n logn) time and a CREW PRAM parallel algorithm with $O(log^2n)$ time and O(n) processors. where n is the number of nodes in the tree.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2149-2170
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• 2017

Application-layer Distributed Denial-of-Service (DDoS) attack is one of the leading security problems in the Internet. In recent years, the attack strategies of application-layer DDoS have rapidly developed. This paper introduces a new attack strategy named Path Vulnerabilities-Based (PVB) attack. In this attack strategy, an attacker first analyzes the contents of web pages and subsequently measures the actual response time of each webpage to build a web-resource-weighted-directed graph. The attacker uses a Top M Longest Path algorithm to find M DDoS vulnerable paths that consume considerable resources when sequentially accessing the pages following any of those paths. A detection mechanism for such attack is also proposed and discussed. A finite-state machine is used to model the dynamical processes for the state of the user's session and monitor the PVB attacks. Numerical results based on real-traffic simulations reveal the efficiency of the attack strategy and the detection mechanism.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.9
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• pp.85-93
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• 1992

In this paper, the new timing optimization algorithm for combinational networks is proposed. First, we introduce the concept of P-path redundancy which is the extension of redundancy concept used in the testing of combinational networks. In this approach, the critical delay is minimized by removing the P-path redundant side inputs of the critical path, and more accurate timing optimization is possible by systematically considering the statically unsensitizable paths as well as the statically sensitizable paths. It's possible with all previous longest path based approaches that the critical delay of resulting network after timing optimization may be even increased. However, the proposed method guarantees to exclude such a possibility, and can be applied to optimize the timing of combinational networks in technology independent, and dependent phase.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.742-744
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• 2001

이 논문은 n-차원 스타 그래프 S$_{n}$, n$\geq$4에서 정점과 에지 고장의 수가 n-3 이하일 때, 임의의 두 고장이 아닌 정점 사이에 길이가 두 정점의 색이 같으면 n!-2f$_{v}$ -2 이상이고, 색이 다르면 n!-2f$_{v}$ -1 이상인 경로가 존재함을 보인다. 여기서 f$_{v}$ 는 고장인 정점의 수이다. 이 결과를 이용하면 고장의 수가 n-3이하일 때, 임의의 고장이 아닌 에지를 지나는 길이 n!-2f$_{v}$ 이상인 사이클을 설계할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.497-507
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• 1993

Four truncation selection schemes (SSs) were framed to predict and compare the age structures and genetic responses under the influence of various factor employing the scheme-specific algorithms. Two paths of selection, sires (bulls' sires) and dams (bulls' dams) to breed young bulls were considered. Among variable factors, four levels (0.3, 0.5, 0.7, 0.9) of precision of evaluation, five levels (0.0, 0.05, 0.10, 0.15, 0.20 genetic standard deviation) of genetic differences among age classes and 4 levels of proportions selected (for bulls' sire, 0.05, 0.10, 0.125, 0.25, and for bulls' dams 0.02, 0.04, 0.05, and 0.10) contemplated on both paths of selection. The number of age classes for bulls' dams and bulls' sires were 4 or 8 and 2 or 4, respectively. The stayability across age classes for bulls' dams was assumed to be 0.80 or 0.60. The candidates for selection for bulls' sires were equally distributed (0.5 or 0.25) across the age classes. The SS1 (selection on same proportions as candidates' distribution) revealed longest generation lengths and lowest yearly genetic responses. The average ages were youngest and yearly genetic responses were highest in SS4 (selection at each age-specific truncation point with the same average genetic superiority of selected parents across the ages) and followed by SS3 (selection at each agespecific truncation point with same predicted genetic values) and SS2 (selection at common truncation point on phenotypic values) in a population with overlapping generations. The results revealed the importance of choosing suitable selection scheme to acquire maximum yearly genetic responses especially when the genetic differences among age classes are large and the precision of evaluation is relatively low.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.5_6
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• pp.195-201
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• 2007

A minimum terminal path decomposition of a tree is defined as a partition of the tree into edge-disjoint terminal-to-terminal paths that minimizes the weight of the longest path. In this paper, we present an $O({\mid}V{\mid}^2$time algorithm to find a minimum terminal path decomposition of trees. The algorithm reduces the given optimization problem to the binary search using the corresponding decision problem, the problem to decide whether the cost of a minimum terminal path decomposition is at most l. This decision problem is solved by dynamic programing in a single traversal of the tree.

• Korean Institute of Interior Design Journal
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• v.18 no.1
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• pp.89-98
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• 2009

As the quality of life Increases, most people are much interested in their health. The latest knowledge and concepts are newly employed and consistently extended in the field of medical facilities as well. The purpose of this study is to investigate space-structural features of dental clinics, to analyze space components in two aspects, the function and the moving path, to provide with base materials for interior design research, and, as a result, to contribute to the improvement of dental clinics. The visitor survey method was implemented in five dental offices haying opened since 2000. The survey results show that each area is distributed as follows; the consultation room is the largest, the waiting space is secondly largest, and the facility area of medical assistance and administration is the smallest. The consultation space can be designed as semi-opened or opened. Considering moving paths, each should not be too long for the communication between doctors and patients, and for the effective medical examination and treatment. The survey indicates medical assistants have the longest moving path because they fully utilize every space. Based on the survey results described above, more systematic in-depth studies should be performed in the future.

• Archives of design research
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• v.12 no.3
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• pp.227-234
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• 1999

We paid attention to the fact that a project will always tend to increase in size even if its scope is narrowing. The complexities and multidisciplinary aspects of projects require that the many parts should be put together so that the prime objectives- performance, time, and cost- are met. These aspects lead to the use of teams to solve problems that used to be solved by individuals. Firstly, We surveyed the design companies and their clients on the design projects, and categorized the design task into 5 phases, that are marketing, planning, idea development, presentation, and follow-up. Among the phases, the presentation has the most difficult task, longest processing time, and highest cost, whereas idea development phase has relatively low cost, longer processing time, and more difficult task. Most of the companies used to be faced several bottlenecks on their design projects - time control, budget control, and resource control. Secondly, for improving the project managing process, we adopted that dividing and analyzing the sub critical paths may help in the effective managing.(Badiru, Adedeji B., 1995) Some critical paths require almost as much attention as the critical path since they have a high potential of becoming critical when changes occur in the network. Therefrom we suggest the Total task weight(Gt) as a management formula for the design project management.${Gt=\mathrm{T}\ast\leftthreetimes\ast1/100}$<\TEX> ( Gt = Total task weight, mathrm{T} = Task Weight, \leftthreetimes= Criticality ) Thirdly, In order to support to managing for the design projects, we set up an application system, which is graphically planning and implementing a complex undertaking. It is helpful to make the control of a project easy. The DPMS(Design Project Management System), which has two sub system. One is Project Screening System(PSS), and another Project Managing System(PMS). In PMS, we divided the design project into three modules; Project Planning, Project Implementation, and Project Evaluation. As a result, the DPMS will contribute to supply the control of a project easily and effectively. Also teams are used for making decisions and taking action with the DPMS. But we need to get further studies on the relationships between the whole project and its tasks.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.595-602
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• 2018

Network-based scheduling methods can be classified into CPM method and PERT method. In the network scheduling chart, critical path can be estimated by performing the forward calculation and the backward calculation though the paths in the network chart. In PERT method, however, it is unreasonable to simply estimate the critical path by adding the sum of the activity durations in a specific path, since it does not incorporate probabilistic concept of PERT. The critical path of a PERT network can change according to the target period and deviation, and in some cases, the expected time of the critical path may not be the path with longest expected time. Based on this concept, this study proposes a technique to derive the most-likely critical path by comparing the sum of estimated time with the target time. It also proposes a method of systematically deriving all alternate paths for a network of repetitive activities. Case studies demonstrated that the most-likely critical path is not a fixed path and may vary according to the target period and standard deviation. It is expected that the proposed method of project duration forecasting will be useful in construction environment with varying target date situations.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.365-374
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• 2005

Schedulability analysis is necessary to build reliable embedded real-time systems. For schedulability analysis, worst-case execution time(WCET) analysis that computes upper bounds of the execution times of tasks, is required indispensably. WCET analysis is done in two phases. The first phase is high-level analysis that analyzes control flow and finds longest paths of the program. The second phase is low-level analysis that computes execution cycles of basic blocks taking into account the hardware architecture. In this thesis, we design and implement integrated WCET analysis tools. We develop the WCET analysis tools for XScale-based system called WATER(WCET Analysis Tool for Embedded Real-time system). WATER consist of high-level flow analyzer and low-level execution time analyzer. Also, We compare real measurement for execution of program with analysis result calculated by WATER.