• Ocean and Polar Research
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• v.25 no.4
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• pp.483-491
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• 2003

Since the red grouper was declared overfished, the Gulf of Mexico Fishery Management Council must prepare a rebuilding plan considering the following alternative management policies: a Total Allowable Catch (TAC), 5-month season closure, 1800-pound trip limit, and a 50-fathom longline boundary. This study was aimed at evaluating the effects of proposed policies for rebuilding the red grouper stock in a 10-year period by developing a bioeconomic model. Under the assumption that the recreation sector was held to its share of TAC (24% of the total quota), the target stock biomass goal was attained in all policies. The NPV was the largest in the 5-month season closure policy if the output price did not fall. There were distributional effects on the different components of the fleets in the 1800-pound trip limit and the 50-fathom longline boundary policy.

• The Journal of Fisheries Business Administration
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• v.35 no.1
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• pp.1-22
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• 2004

Since the red grouper stock was initially declared to be overfished by the NMFS in September 2002, the Gulf of Mexico Fishery Management Council must prepare for the red grouper rebuilding plan considering the following alternative management policies: Total Allowable Catch(TAC), 5 - month season closure, 1800 - pound trip limit, and 50 - fathom longline boundary. The first concern the Council has is to evaluate the effects of recommended policies and the second is to analyze the impact of management policies on yellow edge grouper. This is because the fleets harvest red grouper also catch yellowedge grouper, the regulations on red grouper are likely to allow fishing effort to be distributed into yellowedge grouper. Therefore, this study is aimed at evaluating the biological and economic effects of management policies considering simultaneously the impact of red grouper regulations on yellow edge grouper by developing a combined red grouper and yellowedge grouper bioeconomic model. The overall results indicate that management policies for red grouper would adversely affect the yellowedge grouper stock if yellowedge grouper is not protected by its regulations. The TAC policy has the most serious impact on the yellowedge grouper stock, while the 1800 - pound trip limit policy minimizes the reduction in the yellowedge grouper stock. However, the target stock size of red grouper is achieved as well as the largest net present value of returns is gained in the TAC policy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.147-152
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• 2002

Effect of lip shape on the hole flangeability of high strength steel sheets is investigated. Circular plates of various hole sizes are tested and the variation of lip length as well as the variation of thickness on the sectional views of the finished lip were studied. The conventional hole flanging process is limited to a certain limit hole diameter below which failure will ensue during the hole expansion. The intention of this work is to examine the effect of lip shape on the flangeability of TRIP steel and Ferrite-Bainite duplex steel and find out major parameters which can affect flanging shape of high strength hot rolled steels. Over the ranges of conditions investigated, the minimum hole diameter of F+B steel is better than TRIP steel. while, the lip-shape accuracy of TRIP steel is better than that of F+B steel. although the tensile strength and elongation of %P steel are superior than those of Ferrite-Bainite duplex steel, the flangeability is found to be not so strongly sensitive to the tensile properties but sensitive to displacement on the circumferential direction of hole edge.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.50-52
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• 2008

We have limited the transfer power to capital area below a certain level which is called "The Capital Area Transfer Power Limit", and calculated on every Thursday for the application next week. This level is very important in our network operation, because if this level is not set properly, our power network can be fallen under great danger in case of a fault among the transfer power line. But the calculation procedure for the limit level is so complicated and iterative that it mace us spend much time and do much work. So, when a sudden trip of the related facility to the limit level we can't recalculate the limit level fast enough. And this can drop our network reliability below our standards, therefore our network can be dangerous. To avoid this kind of problems, we have figured out a method to calculate simply the limit level. That method uses the index related to the level. We think this method can make short of the calculation procedures for the level. This paper deals with the simplified method for the calculation of the level limit.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.287-296
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• 2017

Although emission regulations have been gradually strengthened in the past decade, the road transport section remains the most important source of NOx emission in air pollution. One reason is that there has been an increase in the proportion of diesel vehicles and in the volume of traffic. In addition, the certification procedure for standard emission limit does not sufficiently reflect real traffic condition and various driving patterns. Therefore, the European Commission(EC) has recently come up with the RDE-LDV(Real driving emissions-light duty vehicle) regulations, and the Ministry of Environment in Korea has been conducting research on evaluating RDE-LDV with PEMS(Portable Emission Measurement Systems). According to the trip requirements of the 2nd RDE package announced by the EC, the objectives of the present study include the development of Korean RDE routes to reflect domestic traffic and road conditions. Based on the results, both RDE routes are in correct compliance with RDE-LDV regulations, including trip requirements and trip dynamics. KOR-NIER Route 1, in particular, has a higher driving load in rural driving with regard to excessive gradient of elevation compared to KOR-NIER Route 2, including relatively plane rural driving.

• Nuclear Engineering and Technology
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• v.16 no.2
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• pp.106-115
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• 1984

Core safety limits define reactor operating conditions and parameters that will assure fuel rod and reactor system's integrity. Limiting safety system settings (LSSS) programmed into reactor protection system (RPS) then ensure a rapid reactor trip to prevent or suppress conditions which might violate the core safety limits. Generation of the LSSS must properly take into account uncertainties in both calculated and measured parameters in order to assure, with an appropriate degree of confidence, that the RPS will protect the core safety limits. Reviewed in this report are Westinghouse RPS setpoint generation philosophy, methodology of safety limit development and LSSS generation procedure. The Westinghouse RPS trip setpoint generation methodology has been established based on the calculation of core safety limits and the selection of LSSS allowing appropriate uncertainties in a conservative manner. Such conservative values of setpoint assure a high degree of core protection against fuel melting and occurrence of DNB.

• Nuclear Engineering and Technology
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• v.30 no.3
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• pp.222-234
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• 1998

The Westinghouse OT$\Delta$T DNB protection logic heavily restricts the operation region by applying the same logic for a full range of operating pressure in order to maintain its simplicity. In this work, a fuzzy neural network method is used to estimate the DNB protection limit using the measured average temperature and pressure of a reactor core. Fuzzy system parameters are optimized by a hybrid learning method. This algorithm uses a gradient descent algorithm to optimize the antecedent parameters and a least-squares algorithm to solve the consequent parameters. The proposed method is applied to Yonggwang 3&4 nuclear power plants and the proposed method has 5.99 percent larger thermal margin than the conventional OT$\Delta$T trip logic. This simple algorithm provides a good information for the nuclear power plant operation and diagnosis by estimating the DNB protection limit each time step.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.4
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• pp.44-53
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• 2016

The era of Big Data has come and the importance of Big Data has been rapidly growing. The part of transportation, the Four-Step Travel Demand Model(FSTDM), a traditional Trip-Based Model(TBM) reaches its limit. In recent years, a traffic demand forecasting method using the Activity-Based Model(ABM) emerged as a new paradigm. Given that transportation means the spatial movement of people and goods in a certain period of time, transportation could be very closely associated with spatial data. So, I mined Spatial Big Data from SNS. After that, I analyzed the character of these data from SNS and test the reliability of the data through compared with the attributes of TBM. Finally, I built a database from SNS for the operation of ABM and manipulate an ABM simulator, then I consider the result. Through this research, I was successfully able to create a spatial database from SNS and I found possibilities to overcome technical limitations on using Spatial Big Data in the transportation planning process. Moreover, it was an opportunity to seek ways of further research development.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.7
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• pp.67-74
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• 2009

This paper describes the speed control functions of the typical steam turbine speed controllers and the test results of generator load rejection simulations. The goal of the test is to verify the speed controller's ability to limit the steam turbine's peak speed within a predetermined level in the event of generator load loss. During normal operations, the balance between the driving force of the steam turbine and the braking force of the generator load is maintained and the speed of the turbine-generator is constant. Upon the generator's load loss, in other word, the load rejection, the turbine speed would rapidly increase up to the peak speed at a fast acceleration rate. It is required that the speed controller has the ability to limit the peak speed below the overspeed trip point, which is typically 110[%] of rated speed. If an actual load rejection occurs, a substantial amount of stresses will be applied to the turbine as well as other equipments, In order to avoid this unwanted situation, not an actual test but the other method is necessary. We are currently developing the turbine control system for another nuclear power plant and have plan to do the simulation suggested in this paper.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.34-38
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• 2006

In the wireless network, TCP performs poorly because it was originally designed for wired networks and does not take into consideration wireless characteristics such as mobility, high-loss probability, and hidden-terminal problems. In particular, in the wireless multi-hop networks, a large congestion window increases the probability of contention and packet losses, and TCP performance is degraded severely as a result. So, it is necessary to limit the TCP congestion window size in order keep the probability of contention loss in the system to a minimum. In this paper, we propose a new scheme for determining the maximum congestion window size based on the measured bandwidth and Round-Trip-Time (RTT). Using ns-2 simulation, we show that the proposed scheme reduces the probability of packet contention and improves TCP performance.