• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.1
• /
• pp.95-104
• /
• 2016

To make a firing table of artillery with trajectory simulation, a precise trajectory model which corresponds with real firing test is required. Recent 4-DOF modified point mass trajectory model is considered accurate as a theoretical model, but fitting coefficients are used in calculation to match with real firing test results. In this paper, modified point mass trajectory model is presented and method of setting ballistic coefficient is introduced by applying optimization algorithms. After comparing two different algorithms, Particle Swarm Optimization and Covariance Matrix Adaptation - Evolutionary Strategy, we found that using CMA-ES algorithm gives fine optimization result. This fitting coefficient setting method can be used to make trajectory simulation which is required for development of new projectiles in the future.

• Journal of Engineering Education Research
• /
• v.15 no.3
• /
• pp.40-46
• /
• 2012

This paper deals with an example of the engineering education through the SE-based development of an underwater-robot kit model. It has a purpose of establishing the example of a SE-based development by undergraduate through executing the requirement and functional analysis, hardware and software design, manufacturing, test and evaluation for developing the model. In addition, it also has a purpose of establishing the basis of the development of an optimized underwater-robot kit through understanding the weight and buoyancy characteristics and the actuation and propulsion characteristics of the developed model.

• Nuclear Engineering and Technology
• /
• v.52 no.8
• /
• pp.1834-1846
• /
• 2020

The SMART (System-integrated Modular Advanced ReacTor) is an integral-type small modular reactor developed by KAERI (Korea Atomic Energy Research Institute). This paper discusses the development of a dynamic equivalent model of the SMART control rod drive mechanism that can be efficiently utilized for complicated analysis during the design of the SMART. A semi-empirical approach is used to develop the equivalent model; that is, the equivalent model is defined analytically and verified empirically. Two types of tests, dynamic characteristics tests and seismic loading tests, are conducted for the development and verification of the dynamic equivalent model, respectively. Acceleration response spectra from the seismic analysis based on the developed equivalent model show good agreement with those from the seismic loading tests.

• Journal of Korean Society of Rural Planning
• /
• v.17 no.1
• /
• pp.59-65
• /
• 2011

Re-visitation have an effect on dependent variables of regional tourism demand model. This study focused on the re-visitation impacts of consideration on sustainable tourism development of tourists as a new factors of tourism. Based on literature reviews, 11 variables were selected, a questionnaire survey was given to 406 tourists divided into 5 tourism sites at Chuncheon city, and logit model and probit model were used for analysis. The fitness levels of two models were very significant(p=0.0000). The study results suggest that the likelihood of the rural tourist to make a return visit is influenced by recognition of sustainable tourism, purchase of souvenir and farm produce, visitation of regional shops, conversation with regional residents, residents' participation on development, age and marriage. The results of such re-visitation demand can provide information for regional development strategies. The approach to re-visitation research impacts of consideration on sustainable tourism development is expected to become a useful foundation in studying on sustainable regional development.

• Journal of the Korean Society of Systems Engineering
• /
• v.4 no.1
• /
• pp.11-18
• /
• 2008

As a government agency or the Government-donated Research Institute or industrial research institute is intended to develop a product or to construct a system such as a railway safety systems by research and development process, a life cycle model leading a product development or a research and development is essential to them to systematically and effectively progress it. In this paper, the refined life cycle model to effectively conduct the national railway safety project consists of the life cycle phases and their detail descriptions with reference to other life cycle model in the international standard and the other national guidance and other industrial domain such as ship-building, weapon system, and aerospace areas, the proposed life cycle model in the paper considerably reflects the characteristics of the traditional research and development project in railway safety domain. A guidance of a life cycle model which based on lots of the life cycle model in other domains proposes additionally.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.2
• /
• pp.163-170
• /
• 2016

Tropospheric delay is one of the largest error source in pseudolite navigation system. Because a pseudolite is installed on the ground and transmits its signal to a user in the air or on the ground, the conventional tropospheric delay model developed for a satellite navigation doesn't work properly. In this paper, performance analysis of several pseudolite tropospheric delay models has been done using meteorological data. Based on the result, a new compensation method for Hopfield model has been proposed.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.1
• /
• pp.22-30
• /
• 2021

The ship wake generated by rotation of the propeller yields changes of characteristics of sound wave such as attenuation and scattering. To develope a battle field environment simulator for military purposes, it is very important to understand acoustical properties of ship wake. Existing research results have limitations in direct application because they performed under simple conditions or model ships were applied. In this study, we developed a ship wake generation model based on the ship's geometric wake distribution theory. The model can provide spatial distribution and void fraction with various marine environments as well as ship size. Through the developed model, geometric distribution features of ship wake according to the ship's maneuvering conditions were successfully simulated. In addition, changes of the bubble void fraction with time at any location within the battle field environment were identified. Therefore, the developed model is expected to be used in the development of a simulator to measure the acoustic characteristics of the ship wake.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.18 no.2
• /
• pp.167-172
• /
• 2015

In this paper, we have compared some radio propagation models in order to verify the performance of W.C.Y LEE propagation model in mountain area. The four propagation models, which are Okumura-Hata, ITU-R P.525, Egli and W.C.Y. LEE, are analyzed by comparing the differences between measured values and propagation loss estimation values. And a correction method for W.C.Y LEE model is suggested to improve the performance of W.C.Y. LEE model with measured data in mountain area. Simulation results show that the estimation error using W.C.Y LEE model is the lowest among four propagation models. Also, the results show that the corrected W.C.Y LEE model with suggested method improves the performance of propagation loss estimation.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.1
• /
• pp.16-25
• /
• 2016

In this paper, we suggest a quantitative management scheme to accomplish effective weapon systems test and evaluation service(T&E). The Capability Maturity Model Integration(CMMI) process model has been introduced and applied for that purpose by the 8th directorate, Agency for Defense Development(ADD). Although a CMMI process model was developed focusing on the software development, systematic approaching scheme in the CMMI process model can be utilized for the quantitative management implementation of a weapon systems T&E service. To manage a T&E service quantitatively, at first, organizational performance objectives and sub processes are established, and then each performance indicators and performance base lines are followed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.6
• /
• pp.554-560
• /
• 2019

In this study, after applying the finite failure NHPP Rayleigh distribution model and NHPP Inverse Rayleigh distribution model which are widely used in the field of software reliability to the software development cost model, the attributes of development cost and optimal release time were compared and analyzed. To analyze the attributes of software development cost, software failure time data was used, parametric estimation was applied to the maximum likelihood estimation method, and nonlinear equations were calculated using the bisection method. As a result, it was confirmed that Rayleigh model is relatively superior to Inverse Rayleigh model because software development cost is relatively low and software release time is also fast. Through this study, the development cost attributes of the Rayleigh model and the Inverse Rayleigh model without the existing research examples were newly analyzed. In addition, we expect that software developers will be able to use this study as a basic guideline for exploring software reliability improvement method and development cost attributes.