• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.896-904
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• 2017

Several Generation IV nuclear reactor concepts have goals for optimizing investment recovery through phased introduction of multiple units on a common site with shared facilities and/or reconfigurable energy conversion systems. Additionally, small modular reactors are suitable for remote deployment to support highly localized microgrids in isolated, underdeveloped regions. The long-term economic viability of these advanced reactor plants depends on significant reductions in plant operations and maintenance costs. To accomplish these goals, intelligent control and diagnostic capabilities are needed to provide nearly autonomous operations with anticipatory maintenance. A nearly autonomous control system should enable automatic operation of a nuclear power plant while adapting to equipment faults and other upsets. It needs to have many intelligent capabilities, such as diagnosis, simulation, analysis, planning, reconfigurability, self-validation, and decision. These capabilities have been the subject of research for many years, but an autonomous control system for nuclear power generation remains as-yet an unrealized goal. This article describes a functional framework for intelligent, autonomous control that can facilitate the integration of control, diagnostic, and decision-making capabilities to satisfy the operational and performance goals of power plants based on multimodular advanced reactors.

• Journal of Veterinary Science
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• v.24 no.1
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• pp.4.1-4.16
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• 2023

Background: In vitro culture of preantral follicles is a promising technology for fertility preservation. Objectives: This study aims to investigate an optimized three-dimensional (3D) fetal bovine serum (FBS)-free preantral follicle culture system having a simple and easy operation. Methods: The isolated follicles from mouse ovaries were randomly divided in an ultra-low attachment 96-well plates supplement with FBS or bovine serum albumin (BSA) culture or encapsulated with an alginate supplement with FBS or BSA culture. Meanwhile, estradiol (E₂) concentration was assessed through enzyme-linked immunosorbent assay of culture supernatants. The diameter of follicular growth was measured, and the lumen of the follicle was photographed. Spindle microtubules of oocytes were detected via immunofluorescence. The ability of oocytes to fertilize was assessed using in vitro fertilization. Results: The diameters were larger for the growing secondary follicles cultured in ultra-low attachment 96-well plates than in the alginate gel on days 6, 8, and 10 (p < 0.05). Meanwhile, the E2 concentration in the BSA-supplemented medium was significantly higher in the alginate gel than in the other three groups on days 6 and 8 (p < 0.05), and the oocytes in the FBS-free system could complete meiosis and fertilization in vitro. Conclusions: The present study furnishes insights into the mature oocytes obtained from the 3D culture of the preantral follicle by using ultra-low attachment 96-well plate with an FBS-free system in vitro and supports the clinical practices to achieve competent, mature oocytes for in vitro fertilization.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.327-334
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• 2024

Amidst the burgeoning research on autonomous ships, there has been a marked increase in the development of new systems and equipment for these vessels. This study identifies specific assets and functional requirements essential for managing autonomous ships, and presents a system architecture applicable to conventional and autonomous vessels alike. The recommended fleet asset management system encompasses ship information, maintenance, crew, and operational management. Assets specific to autonomous ships include the MASS rating within ship information, advanced software and hardware for maintenance, and remote operators in the crew management. These asset functions are managed through separate, modular systems that permit easy attachment and detachment, hence ensuring compatibility with both traditional and autonomous ships. Moreover, the system is web-based which facilitates access through an internet environment without necessitating the installation of any program.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.8-14
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• 2023

In various industrial sites, piping systems play an essential role in stable fluid supply and pressure maintenance. However, these systems are constantly exposed to risks of earthquakes, explosions, fires, and leaks, which can result in casualties or serious economic losses. With rapid advancements in the industry, different-sized piping systems have been launched; however, there are not enough maintenance personnel for troubleshooting and responding to situations where damages occur to piping systems. This increases the need for introducing autonomous damage management systems. In this study, a lab-based piping system was designed and manufactured by referring to the piping system of a naval ship to analyze the effectiveness of autonomous damage management systems. By using this testbed, a representative algorithm, the hydraulic resistance control algorithm, was realized and examinedIn addition, the difference between the averaged pressure and normalized pressure was introduced to improve the performance of the existing algorithm, which faces some limitations with regard to sensor noise and back pressure from the rupture-simulated pipeline part.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.1
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• pp.34-45
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• 2013

Due to its self-configuring nature, the tactical mobile ad hoc network is used for communications between tactical units and the command and control center (CCC) in battlefields, where communication infrastructure is not available. However, when a tactical unit moves far away from the CCC or there are geographical constraints, the data link between two communicating nodes can be broken, which results in an invalid data route from the tactical units to CCC. In order to address this problem, in this paper we propose a hierarchical connectivity maintenance scheme, namely ADLCoM (Autonomous Data Link Connectivity Maintenance). In ADLCoM, each tactical unit has one or more GW (gateway), which checks the status of data links between tactical units. If there is a possibility of link breakage, GWs request ground or aerial unmanned vehicles to become a relay for the data link. The simulation results, based on tactical scenarios, show that the proposed scheme can significantly improve the network performance with respect to data delivery ratio.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.64-74
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• 2003

The unstructured system requires different system designs and realizations according to the environmental factors of the situation, as well as frequent system changes and revisions. Being realized off-line in most of the cases, such a system is in a great demand for maintenance and repair and very difficult to execute the central intensive management. In such a case, the unstructured system is usually fit into a single standardized framework, which makes it impossible to present the accurate picture of the real world and to properly reflect the features of the system. In an attempt to solve these problems, a new concept of system development theory was suggested; it is called the autonomous system, which enables each module to be designed autonomously and allows easy maintenance and repair An example of system realization on the web using the development methodology of this autonomous system was Presented.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.1-11
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• 2021

Piping systems comprising pumps and valves are essential in the power plant, oil, and defense industry. Their purpose includes a stable supply of the working fluid or ensuring the target system's safe operation. However, piping system accidents due to leakage of toxic substances, explosions, and natural disasters are prevalent In addition, with the limited maintenance personnel, it becomes difficult to detect, isolate, and reconfigure the damage of the piping system and recover the unaffected area. An autonomous recovery piping system can play a vital role under such circumstances. The autonomous recovery algorithms for the piping system can be divided into low-pressure control algorithms, hydraulic resistance control algorithms, and flow inventory control algorithms. All three methods include autonomous opening/closing logic to isolate damaged areas and recovery the unaffected area of piping systems. However, because each algorithm has its strength and weakness, appropriate application considering the overall design, vital components, and operating conditions is crucial. In this regard, preliminary research on algorithm's working principle, its design procedures, and expected damage scenarios should be accomplished. This study examines the characteristics of algorithms, the design procedure, and working logic. Advantages and disadvantages are also analyzed through simulation results for a simplified piping system.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1633-1642
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• 2002

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.

• The Journal of Korea Robotics Society
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• v.5 no.2
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• pp.120-126
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• 2010

This paper presents to study the path tracking method of AGV(autonomous guided vehicle) which has a laser guidance system. An existing automatic guided vehicles(AGVs) which were able to drive on wired line only had a automatic guidance system. However, the automatic guidance systems that those used had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the laser guidance system which is consisted of a laser navigation and gyro, encoder. That is robust against noise, and flexible according to working environment through sensor fusion. The laser guidance system can do a perfect autonomous driving. However, the commercialization of perfect autonomous driving system is difficult, because the perfect autonomous driving system must recognize the whole environment of working space. Hence, this paper studied the path tracking of AGV using laser guidance system without wired line. The path tracking method is consisted of virtual path generation method and driving control method. To experiment, we use the fork-type AGV which is made by ourselves, and do a path tracking experiments repeatedly on same experimental environment. In result, we verified that proposed system is efficient and stable for actual fork-type AGV.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.351-360
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• 2022

Autonomous vehicles require precise knowledge of their position, velocity and orientation in all weather and traffic conditions in any time. And, these information is effectively used for path planning, perception, and control that are key factors for safety of vehicle driving. For this purpose, a high precision GNSS technology is widely adopted in autonomous vehicles as a core localization and navigation method. However, due to the lack of infrastructure as well as cost issue regarding GNSS correction data communication, only a few high precision GNSS technology will be available for future commercial autonomous vehicles. Recently, a high precision GNSS sensor that is based on a Broadcast-RTK system to dramatically reduce network maintenance cost by utilizing the existing broadcasting network is released. In this paper, we present the performance test result of the broadcast-RTK-based commercial high precision GNSS receiver to test the feasibility of the system for autonomous driving in Korea. Massive measurement campaigns covering of Korea region were performed, and the obtained measurements were analyzed in terms of ambiguity fixing rate, integer ambiguity loss recovery, time to retry ambiguity fixing, average correction information update rate as well as accuracy in comparison to other high precision systems.