• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.255-258
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• 2003

In this paper there are different methods used to study the voltage stability, such as the P-V curve method. Jacobian method and the voltage collapse proximity indicator(L-index) method. The P-V curve method is to check operating margin from the maximum operating point. The Jacobian method is to check the eigenvalue or the minimum singular value of the load flow Jacobian matrix. If the power system is unstable, one of the eigenvalues, at least, has crossed the imaginary axis. The L-index method is to quantify how to close a particular operating point. This paper describes these methods to select the best location of FACTS and demonstrate the effectiveness of STATCOM of voltage stability on the IEEE 9-bus system.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.195-196
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• 2015

This paper investigates the design of coupled inductor for minimum inductor current ripple in rapid traction battery charger systems. Based on the general circuit model of coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor which corresponds to a minimum inductor ripple current becomes -0.5, i.e. a complete inverse coupling without leakage inductance, as the steady-state duty ratio operating point approaches 1/3 or 2/3. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the steady-state duty ratio operating point approaches either zero or one. Coupled inductors having optimal coupling factor can minimize the ripple current of inductor and battery current resulting in a reliable and efficient operation of battery chargers.

• Journal of Power System Engineering
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• v.16 no.5
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• pp.55-62
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• 2012

Centrifugal compressors are widely used and each operating condition is different. However, it cannot be manufactured according to the every operating condition. In the this study, performance of compressor was evaluated with various rotational speeds of impeller and various stagger angles of diffuser in order to apply a typical model widely. A centrifugal compressor was designed and manufactured based on the design point. On this machines, an experiment was conducted and the performance was predicted at off-design point. The performance prediction was validated with the experimental result and the numerical result. Although the isentropic efficiency on the prediction was slightly lower than that on the experimental result due to the heat loss in the experiment, the pressure ratio was predicted well and also the predicted results were matched well with the numerical results. When the rotational speed of the impeller and the stagger angle of the diffuser were changed together, the compressor can be worked in the high efficiency region and avoided operating in the stall region.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.463-469
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• 1995

The point-kinetics reactor system which is subject to feedback effects may have multiple steady-state solutions for some operating conditions. A necessary and sufficient condition for multiple steady-state solutions of the point-kinetics reactor feedback system for an external input reactivity is obtained through their theoretical approach. If and only if the steady-state feedback reactivity of the reactor system is not strictly monotonic on some values of the feedback variables, then the reactor system has multiple steady-state solutions for the equilibrium operating conditions corresponding to the values of the feedback variables. Also, if and only if the steady--state feedback reactivity is strictly monotonic on all the feedback variables, then the reactor system has only one steady-state solution for all the operating conditions.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.192-196
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• 1988

This paper presents a feasibility study related to the design of a linear multivariable compensator for a model of boiler-turbine system. The nonlinear dynamics are linearized at a operating condition. At the operating point an LQG/LTR compensator is designed. Simulations are included to illustrate the usefulness of this linear multivariable control law.

• Journal of Power Electronics
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• v.18 no.3
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• pp.826-840
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• 2018

This paper presents a distributed maximum power point tracking (DMPPT) algorithm based on the reference voltage perturbation (RVP) method for the PV modules of a series PV string. The proposed RVP-DMPPT algorithm is developed to accurately track the maximum power point (MPP) for each PV module operating under all atmospheric conditions with a reduced hardware overhead. To study the influence of parameters such as the controller reference voltage ($V_{ref}$) and PV current ($I_{pv}$) on the PV string voltage, a small signal model of a unidirectional differential power processing (DPP) based PV-Bus architecture is developed. The steady state and dynamic performances of the proposed RVP DMPPT algorithm and small signal model of the unidirectional DPP based PV-Bus architecture are demonstrated with simulations and experimental results. The accuracy of the RVP DMPPT algorithm is demonstrated by obtaining a tracking efficiency of 99.4% from the experiment.

• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.51-56
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• 2022

This paper presents an Ground Segmentation algorithm to eliminate unnecessary Lidar Point Cloud Data (PCD) in an autonomous driving system. We consider Random Sample Consensus (Ransac) Algorithm to process lidar ground data. Ransac designates inlier and outlier to erase ground point cloud and classified PCD into two parts. Test results show removal of PCD from ground area by distinguishing inlier and outlier. The paper validates ground rejection algorithm in real time calculating the number of objects recognized by ground data compared to lidar raw data and ground segmented data based on the z-axis. Ground Segmentation is simulated by Robot Operating System (ROS) and an analysis of autonomous driving data is constructed by Matlab. The proposed algorithm can enhance performance of autonomous driving as misrecognizing circumstances are reduced.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.180-191
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• 2016

Optimizing energy usage for maximum efficiency is an essential goal for manufacturing plants in every industrial manufacturing sector. The generation and distribution of purifying compressed air is a large expense incurred in practically all manufacturing processes. Not only is the generation and treatment expensive equipment of compressed air, but frequent maintenance and effective operation is also required. As a plant's compressed air system is often an integral part of the production process, it needs to be reliable, efficient, and easy to be maintain. In this paper, we study to find operating method to save energy from the adsorption dryer in the process of purifying compressed air, which is required for a clean room production site in "A" company. The compressed air passes through a pressure vessel with two "towers" filled with a material such as activated alumina, silica gel, molecular sieve or other desiccant material. This desiccant material attracts the water from the compressed air via adsorption. As the water clings to the desiccant, the desiccant particle becomes saturated. Therefore, Adsorption dryer is an extremely significant facility which removes the moisture in the air $70^{\circ}C$ below the dew point temperature while using a lot of energy. Also, the energy consumption of the adsorption dryer can be varied by various operating conditions (time, pressure, temperature, etc). Therefore, based on existing operating experiments, we have searched operating condition to maximize energy saving by changing operating conditions of the facility. However, due to a short experiment period (from September to October), further research will be focused on considering seasonality.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.608-611
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• 2003

A large part of the embedded system, compared with the PC, have low performance CPU and small memory. So the embedded operating system fits the condition of that hardware system. A Single Address Space (SAS) OS has the operating system and all applications in the single address space. The SAS architecture enhances sharing and co-operation, because addresses have a unique interpretation. Thus, pointer-based date structures can be directly communicated and shared between programs at any time, and can be stored directly on storage. The key point of the SAS OS on the embedded system is the low overhead inter-action between programs in process and usage. So SAS OS can be ported on the low performance CPU. In this paper, we design the SAS OS (named emNOS, Embedded Network Operating System) on the ARMTTDMI processor. Finally we show the benefits of the SAS OS on the embedded system.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.87-96
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• 2012

This research overcomes limit of prevention of disasters connection manual that was stopping in existing administrative formality presentation, and allowed purpose in substantial prevention of disasters countermeasure presentation through powerful engineering access. Did operation plan manual Tuesday in contiguity crossing that can reduce confusion by vehicleses that detour by contiguity IC of disaster point to do unusualness ashes in freeway section for this and solve jam-up phenomenon that occur by processing way insufficiency for roundabout way vehicles when happen. Metropolitan areas to target type classification in the highway along the highway adjacent to the intersection at Main Line Blocking optimum operating point analysis and an analysis of countermeasures in case of disaster, the lower the road entering the highway depending on the type of operating at the intersection were different. Depending on the results of analysis, while each point of a disaster, according to the characteristics of geometric conditions, traffic conditions, identify and determine the operating room and the adjacent intersection of media, and building systems to promote the driver if the quick initial response from the impending disaster situations and the safety of drivers can be considered secure.