• Journal of the Korean Society of Systems Engineering
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• v.19 no.1
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• pp.79-90
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• 2023

In principle, R&D of general weapons systems are led by companies or government-funded organizations. In terms of project execution, the defense R&D planning system was reorganized to conduct SE-based project management by integrating the naval ship project execution procedure into the general weapon system R&D procedure. The development progress was confirmed according to the guide for SE application of DAPA, and a technical review meeting was proposed to enter into the each next phase in the R&D process. This paper focuses on improvement for technical review in terms of technical management based on system engineering for R&D mounted weapon systems and the naval surface ship project in preliminary design and detailed design. So, the improvement direction for reviewing the entry criteria for the R&D weapons systems of the naval ship and mounted weapons is proposed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.4
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• pp.333-339
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• 2011

In this work, electrochemical characteristics and optical transmittance of carbon nanotubes (CNTs) counter electrodes which had different amount of CNTs in CNTs slurries were analyzed. Two-step heat treatment processes were applied to achieve well-fabricated CNTs electrode. Three sets of CNTs electrodes and dye-sensitized solar cells (DSSCs) with CNTs counter electrodes were prepared. As the amount of CNTs increased, sheet resistance of CNTs electrode decreased. CNTs electrode with low sheet resistance had low electrochemical impedance and fast redox reaction. On the other hand, in case of CNTs counter electrode with low density of CNTs, performance of the dye-sensitized solar cell was improved due to its high optical transmittance. We found that the transmittance of CNTs counter electrode influence the performance of dye-sensitized solar cells.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.101-108
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• 2019

The domestic duck industry is the sixth-largest among the livestock industries. However, 34.3% of duck houses were the duck houses arbitrarily converted from plastic greenhouses. This type of duck house was difficult to properly manage internal air temperature and humidity environment. Humidity environment inside duck houses is an important factor that directly affects the productivity and disease occurrence of the duck. Although the humidity environments of litters (bedding materials) affect directly the inside environment of duck houses, there are only few studies related to humidity environment of litters. In this study, evaporation rates from litters were evaluated according to air temperature, relative humidity, water contents of litters, and wind speed. The experimental chamber was made to measure evaporation rates from litters. Temperature and humidity controlled chamber was utilized during the conduct of the laboratory experiments. Using the measured data, a multi linear regression analysis was carried out to derive the calculation formula of evaporation rates from litters. In order to improve the accuracy of the multi linear regression model, the partial vapor pressure directly related to evaporation was also considered. Variance inflation factors of air temperature, relative humidity, partial vapor pressure, water contents of litters, and wind speed were calculated to identify multicollinearity problem. The Multiple $R^2$ and adjusted-$R^2$ of regression model were calculated at 0.76 and 0.71, respectively. Therefore, the regression models were developed in this study can be used to estimate evaporation rates from the litter of duck houses.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.6
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• pp.55-63
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• 2022

Odors emitted from pig houses have been a constant root of legal issues in pig farming. These gases are among the main causes of health and mental stresses to nearby communities, so policymakers and researchers continuously study to reduce the concentration of odorous gases from pig facilities. A continuous field experiment proved that the concentration of odor emissions inside the pig houses is highly dependent on ventilation rate, breeding details, and animal activities. However, the standard odor emission rate worldwide widely varies due to differences in pig house designs and ventilation requirements. Thus, this study aimed to measure the odor emission rates, considering the actual condition of selected Korean pig houses, through field measurement. The odor measurements were performed at three different pig production facilities without odor abatement technologies. The target experimental pig houses were buildings for weaning, growing, and fattening pigs. Results showed that the actual ventilation rate in target pig houses falls below the standard ventilation requirement of pigs, resulting in high odor concentrations inside the pig houses.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.2
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• pp.27-32
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• 2006

The emerging standards since 1990's can be classified as 'system standards' (process-oriented standards) and they specify the process of an enterprise and also apply to almost all industries regardless of size, type and products. Notice that the conventional specification-oriented standards present relatively clear criteria even though the structure, performance, and terminology are defined in text-based form. However, the system standards dealing with the processes do not present a coherent guide. Therefore, it is difficult to analyze them with the same viewpoint, thereby resulting in differences in the level of understanding. This study is aimed at graphically modeling the system standards originally described in text-based form. The study has been carried out in the framework of the PMTE (Process, Methods, Tools, and Environment) paradigm. The system standard targeted here is ISO/IEC 15288. Firstly, review of the literature on the systems engineering (SE) standard/process and on the graphic model IDEF0 was done, respectively, for the parts of 'E' and 'M'. Then the SE process of the MIL-STD 499B was applied to ISO/IEC 15288 as 'P'. Finally, the graphical model was generated by AI0Wins as 'T'. As a result, the graphical model-based approach can complement the drawbacks of the text-based form.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1238-1240
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• 2017

본 논문에서는 현재 상용화 된 유모차들이 가지고 있는 불편함 및 예기치 못한 변수로 일어나는 사고에 대응할 수 있는 기능 등 한계점을 극복하고 보완 할 수 있는 기능들을 '스마트 자율 주행 유모차'라는 시스템을 통하여 소개한다. IR-LOCK 센서를 통하여 부모와 유모차 간 일정 거리를 유지하며 센싱 한 데이터를 BLDC 모터로 전송하여 상황에 맞는 움직임을 아두이노에서 제어하는 시스템이다. 몇 가지 예외적인 실험 상황에서는 불안정한 엑츄에이션이 있지만, 정교한 알고리즘을 통하여 최적화를 시켜간다면 완성도가 높은 제품으로 발전할 가능성이 있다. 더 나아가 이 시스템을 유모차에 제한하지 않고, 다른 분야에도 적용시킨다면 매우 기대가 되는 시스템이라고 판단된다.

• Smart Structures and Systems
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• v.1 no.1
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• pp.1-12
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• 2005

This paper describes the area of intelligent systems research as funded by the Civil and Mechanical Systems (CMS) Division of the National Science Foundation (NSF). With developments in computer science, information technology, sensing and control the design of typical machines and structures by civil and mechanical engineers is evolving toward intelligent systems that can sense, decide and act. This trend toward electro-mechanical design is well-established in modern machines (e.g. vehicles, robots, disk drives) and often referred to as mechatronics. More recently intelligent systems design is becoming an important aspect of structures, such as buildings and bridges. We briefly review recent developments in structural control, including the role that NSF has played in their development, and discuss on-going CMS activities in this area. In particular, we highlight the interdisciplinary initiative on Sensors and Sensor Networks and the Network for Earthquake Engineering Simulation (NEES). NEES is a distributed cyberinfrastructure to support earthquake engineering research, and provides the pioneering NEES grid computing environment for simulation, teleoperation, data collection and archiving, etc.

• Smart Structures and Systems
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• v.15 no.6
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• pp.1521-1542
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• 2015

The use of shape memory alloys (SMAs) in dynamical systems has an increasing importance in engineering especially due to their capacity to provide vibration reductions. In this regard, experimental tests are essential in order to show all potentialities of this kind of systems. In this work, SMA springs are incorporated in a dynamical system that consists of a one degree of freedom oscillator connected to a linear spring and a mass, which is also connected to the SMA spring. Two types of springs are investigated defining two distinct systems: a pseudoelastic and a shape memory system. The characterisation of the springs is evaluated by considering differential calorimetry scanning tests and also force-displacement tests at different temperatures. Free and forced vibration experiments are made in order to investigate the dynamical behaviour of the systems. For both systems, it is observed the capability of changing the equilibrium position due to phase transformations leading to hysteretic behaviour, or due to temperature changes which also induce phase transformations and therefore, change in stiffness. Both situations are investigated by promoting temperature changes and also pre-tension of the springs. This article shows several experimental tests that allow one to obtain a general comprehension of the dynamical behaviour of SMA systems. Results show the general thermo-mechanical behaviour of SMA dynamical systems and the obtained conclusions can be applied in distinct situations as in rotor-bearing systems.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.1
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• pp.16-24
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• 2019

In this study, an improved method of setting the RAM goals for surveillance system using OMS/MP and field operations data of similar systems is suggested and a case study of surveillance system A is given. Newly suggested methods for setting the RAM goals consist of the procedures such as On/Off time analysis of configuration equipment based on OMS/MP, field operations data analysis of similar systems, adjustment of preventive maintenance time, the number of corrective maintenances, and TALDT in wartime, introducing new subsystem to reliability structure of surveillance system, and reflecting expert's opinion. A case study of surveillance system A shows that newly suggested method in this study for setting the RAM goals is reasonably acceptable and practically applicable to other similar systems.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.81-93
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• 2015

Steam Reforming H2 Generation (SRH2G) System is a chemical process to produce hydrogen through steam reforming of hydrocarbon. Largely speaking, there are two types of materials for the SRH2G: 1) Oil and coal, and 2)Natural Gas such as shale gas. From the perspective of cost, quality (purity), and environmental burden (pollution), the latter is much more desirable than the former. For this reason, research on SRH2G using natural gas is actively carried out, and implemented and operated in the various industry. In this paper, we develop a natural gas based SRH2G system via systems engineering approach. Specifically, we first derived stakeholder requirements, followed by systems requirements and finally system architecture via a tailored SE process for plant (called Plant Systems Engineering (PSE) process) based on ISO/IEC 15288. The developed method was applied to iron and steel plant as a case study. Through the case study, by the SE approach, we were convinced that a successful system satisfying stakeholders' requirements within the given constraints can be developed, verified and validated.