• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.294-294
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• 2019

The system for predicting flood of river at Flood Control Office is made up of a rainfall-runoff model and FLDWAV model. This system is mainly operating to predict the excess of the flood watch or warning level at flood forecast points. As the demand for information of the management and operation of riverside, which is being used as a waterfront area such as parks, camping sites, and bike paths, high-level forecasts of watch and warning at certain points are required as well as production of lowland flood forecast information that is used as a waterfront within the river. In this study, a technology to produce flood forecast information in lowland areas of the river used as a waterfront was developed. Based on the results of the 1D hydraulic analysis, a model for performing spatial operations based on high resolution grid was constructed. A model was constructed for Andong district, and the inundation conditions and level were analyzed through a virtual outflow scenarios of Andong and Imha Dam.

• Journal of Advanced Navigation Technology
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• v.25 no.5
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• pp.363-369
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• 2021

In this paper, We propose variable cut-off frequency and variable sample rate small-area multi-channel digital filter for telemetry system. Proposed digital filter reduced hardware area by implementing filter banks that can variably use cut-off frequency and sample rate without additional filter banks for an arbitrary cut ratio. In addition, We propose the architecture in which sample rate can variably be selected according to the number of filters that pass through the multiplexer control. By using time division multiplexing (TDM) supported by the finite impulse response (FIR) intellectual property (IP) of Quartus, the proposed digital filter can greatly reduce digital signal processing (DSP) blocks from 80 to 1 compared without TDM. Proposed digital filter calculated order and coefficients using Kaiser window function in Matlab, and implemented using very high speed integrated circuits hardware descryption language (VHDL). After applying to the telemetry system, we confirmed that the proposed digital filter was operating through the experimental results in the test environment.

• Ocean policy research
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• v.33 no.2
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• pp.183-204
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• 2018

Whaling has been banned in Republic of Korea after the declaration of the moratorium on the commercial whaling by the International Whaling Commission (IWC) since 1986. Korean government followed the moratorium immediately. However whale meat market has been kept by the bycaught whales and dolphins. So Korean government established a rule to control and trace whale meat in the market in 2011. The rule has some loopholes to allow illegally taken whale meat smuggle into the market. This study investigates the flaws in the current rule and recommend the way to overcome that defects. The first step is to prevent the entry of the illegal whale meat into the market. Minor change of the current law would be a solution. The next measure is to increase the sampling rate of the whale DNA that allowed to distribute in the market. The DNA database would be a powerful tools to identify illegal whale meat which is existing in the market. Korean government is operating three kind of food traceability systems. However, because of the legal limitations and the opposition of the non-governmental animal rights organizations, it is difficult to include whale meat to the existing systems. So the last step is to establish a new Traceability System with a state-of-the-art IT technology like as blockchain. The three measures mentioned above would increase the transparency in the whale meat market and prevent the entry of the illegal products.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.68-77
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• 2021

In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.77-86
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• 2022

The Republic of Korea is a country in which coastal surveillance is an imperative national task as it is surrounded by seas on three sides under the confrontation between South and North Korea. However, due to Defense Reform 2.0, the number of R/D (Radar) operating personnel has decreased, and the period of service has also been shortened. Moreover, there is always a possibility that a human error will occur. This paper presents specific guidelines for developing an AI learning model for the intelligent coastal surveillance system. We present a three-step strategy to realize the guidelines. The first stage is a typical stage of building an AI learning model, including data collection, storage, filtering, purification, and data transformation. In the second stage, R/D signal analysis is first performed. Subsequently, AI learning model development for classifying real and false images, coastal area analysis, and vulnerable area/time analysis are performed. In the final stage, validation, visualization, and demonstration of the AI learning model are performed. Through this research, the first achievement of making the existing weapon system intelligent by applying the application of AI technology was achieved.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.800-808
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• 2022

The International Maritime Organization adopted the interim standards for ship maneuverability in November 1993 for preventing collision of ships at sea and for protecting the marine environment, and based on the accumulated data, in December 2002, the established standards for ship maneuverability were adopted. However, the standards adopted are those at full load, even keel, and at least 90 % of the ship speed at 85 % of the ship's maximum power. Moreover, these standards have limitations in providing information on maneuverability under actual navigational conditions. Therefore, in this study, frequency analysis AHP analysis techniques were studied by consulting navigational officers, captains, and experts, who have significant knowledge on ship maneuverability, utilization of the current standards, and the information necessary for the operation of the actual ship. The results of this study confirmed that the necessary information on maneuverability for the navigational officer operating the vessel is information about the turning circle at a small angle of 5°-10° and z-test information at maneuvering speed, not sea speed. Additionally, in relation to speed control, additional information on deceleration inertia and acceleration inertia is needed than the information on the stopping ability at sea speed and full loaded condition. The derived results are considered to be useful as basic data for preparing guidelines for ship maneuverability necessary for navigational of icers who operate ships.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.345-353
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• 2022

A wastewater treatment plant (WWTP) is a major gateway for the engineered nano-particles (ENPs) entering the water bodies. However existing studies have reported that many WWTPs exceed the No Observed Effective Concentration (NOEC) for ENPs in the effluent and thus they need to be designed or operated to more effectively control ENPs. Understanding and predicting ENPs behaviors in the unit and \the whole process of a WWTP should be the key first step to develop strategies for controlling ENPs using a WWTP. This study aims to provide a modeling tool for predicting behaviors and removal efficiencies of ENPs in a WWTP associated with process characteristics and major operating conditions. In the developed model, four unit processes for water treatment (primary clarifier, bioreactor, secondary clarifier, and tertiary treatment unit) were considered. Additionally the model simulates the sludge treatment system as a single process that integrates multiple unit processes including thickeners, digesters, and dewatering units. The simulated ENP was nano-sized TiO₂, (nano-TiO₂) assuming that its behavior in a WWTP is dominated by the attachment with suspendid solids (SS), while dissolution and transformation are insignificant. The attachment mechanism of nano-TiO₂ to SS was incorporated into the model equations using the apparent solid-liquid partition coefficient (Kd) under the equilibrium assumption between solid and liquid phase, and a steady state condition of nano-TiO₂ was assumed. Furthermore, an MS Excel-based user interface was developed to provide user-friendly environment for the nano-TiO₂ removal efficiency calculations. Using the developed model, a preliminary simulation was conducted to examine how the solid retention time (SRT), a major operating variable affects the removal efficiency of nano-TiO₂ particles in a WWTP.

• Food Science and Industry
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• v.55 no.2
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• pp.188-202
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• 2022

In the insect industry, as the scope of application of insects is expanded from pet insects and natural enemies to feed, edible and medicinal insects, the demand for quality control of insect raw materials is increasing, and interest in securing the safety of insect products is increasing. In the process of expanding the industrial scale, controlling the temperature and humidity and air quality in the insect breeding room and preventing the spread of pathogens and other pollutants are important success factors. It requires a controlled environment under the operating system. European commercial insect breeding facilities have attracted considerable investor interest, and insect companies are building large-scale production facilities, which became possible after the EU approved the use of insect protein as feedstock for fish farming in July 2017. Other fields, such as food and medicine, have also accelerated the application of cutting-edge technology. In the future, the global insect industry will purchase eggs or small larvae from suppliers and a system that focuses on the larval fattening, i.e., production raw material, until the insects mature, and a system that handles the entire production process from egg laying, harvesting, and initial pre-treatment of larvae., increasingly subdivided into large-scale production systems that cover all stages of insect larvae production and further processing steps such as milling, fat removal and protein or fat fractionation. In Korea, research and development of insect smart factory farms using artificial intelligence and ICT is accelerating, so insects can be used as carbon-free materials in secondary industries such as natural plastics or natural molding materials as well as existing feed and food. A Korean-style customized breeding system for shortening the breeding period or enhancing functionality is expected to be developed soon.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.3
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• pp.163-173
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• 2001

The dynamic behavior characteristics of a small fishing crane for inshore and coastal fishing vessels was experimentally analyzed in order to improve the fishing operation and to reduce considerably manual work of fisherman. The small fishing crane was designed to be controlled electro-hydraulically by means of proportional valves and solenoid valves, and also to be controlled the speed of each operation. The dynamic behavior characteristics was investigated by measuring the changes of parameters such as oil pressure, swing angle of load, load tension, the lifting angle and the swing angle of crane arm when the arms extended in a side way was given a test load. The results obtained are summarized as follows: 1. The designed small fishing crane can be proportionally controlled by means of proportional valves and rapidly by operating the solenoid valves, respectively. The capacity, turning angle, maximum reach of crane were 2 T-M, $180^\circ$, 3.7m, respectively. 2. The vertical change of crane arm on the extension of lifting cylinder was $1.2^\circ$/cm, and the swing speed of crane arm due to the extension of swing cylinder by on/off operations of solenoid valves was $15^\circ$/sec, with the swing period of 1.4 sec and the angle fluctuation of $\pm$11.0$^{\circ}$. 3. When changing simultaneously the horizontal and vertical positions of the lifting load by on/off operations of solenoid valves, the swing and lifting speeds of crane arm were $4.46^\circ$/sec and $6.4^\circ$/sec, respectively. 4. The movements of the designed crane were particularly smooth as they are controlled with the aid of proportional valves than by means of solenoid valves.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.