• Journal of Sensor Science and Technology
• /
• v.11 no.3
• /
• pp.125-131
• /
• 2002

Respiratory air flow rate is necessarily measured for the pulmonary function evaluation. The currently used devices are exposed to the problems of measurement reliability and cross-patient infection. The present study introduced a new technique which converted the bidirectional air flow rate into averaged dynamic pressure based on the famous Bernoulli's energy conservation principle. Single use plastic sensing element was assembled within the flow tube(mouth piece) made of paper, which was named "functional single use flow tube". Experiment demonstrated only ${\pm}1.5%$ relative error in the standard 3L volume measurement procedure well within the error limit suggested by the American Thoracic Society(ATS). Disposable use design completely eliminated cross-patient infection. The present device is best useful and safe for clinical respiratory air flow measurement such as spirometry.

• Fire Science and Engineering
• /
• v.14 no.3
• /
• pp.6-12
• /
• 2000

This paper describes the smoke movement of a fire field model based on a self-developed SMEP(Smoke Movement Estimating Program) code to the simulation of fire induced flows in the two types of compartment space containing the radiation effect under smoke movement in room fire. The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k-$\varepsilon $ turbulence model with buoyancy term. Also it solves the radiation equation using the discrete ordinates method. The result of the calculated smoke temperature containing radiation effect has shown reasonable agreement compared with the experimental data. On the other hand, a difference of a lot was found between the temperature predicted by the SMEP with only convection effect and obtained by the experimental result. This seems to come from the radiation effect of $H_2$O and $CO_2$ gas under smoke productions. Thus, the consideration of the radiation effect under smoke in fire may be necessary in order to produce more realistic result.

• Journal of Korean Society for Geospatial Information Science
• /
• v.17 no.3
• /
• pp.109-114
• /
• 2009

Although island is great worth in ecology, environmental conservation and important territory as a national land for developing the marine, the bottom of the sea and also ecological studying field for the ages to come, it has not been managed because of lack of a scientific surveying. In the case of a cadastral record, inaccessible islands have not been registered in current cadastral record because of the limit of surveying technology in 1910. Therefore, a scientific investigation and systematic management about unregistered islands are necessary. But, a airborne laser scanning system is possible to acquire an accurate positions with digital images about inaccessible islands. Therefore, scientific detection of unregistered islands became possible. This paper presented the results of the shoreline extraction around the Heuksan island using Lidar data and the detection of unregistered islands comparing the cadastral map to the ortho-image. Also, we presented the extraction technique of unregistered islands by calculating their positions and areas. As a result, we extracted effectively 16 unregistered islands around the Heuksan island.

• Journal of Korean Society for Quality Management
• /
• v.48 no.1
• /
• pp.13-27
• /
• 2020

Purpose: The purpose of this study is to present a recoil measurement and analysis of K2 rifle for the development of a virtual reality marksmanship training in the Republic of Korea Army. Methods: For the recoil measurement, a test-bed is built by a barrel that has exact dimensions of K2 rifle and three piezoelectric pressure sensors mounted on the barrel. Data of over 200 rounds of 5.56mm M193 and K100 bullets are collected and analyzed from live fire experiments. For the recoil analysis, both the free recoil method and the gas exhaust aftereffect method are used to calculate a recoil velocity, momentum and kinetic energy of K2 rifle by applying the law of conservation of momentum. In addition, a new method is proposed that uses the third law of motion and the chamber pressure model for the recoil measurement Results: The results show how different between the previous and proposed methods with respect to M193 and K100 bullets of K2 rifle. In M193, the free recoil method demonstrates 1.113, 4.197, and 2.335, the gas exhaust aftereffect method computes 1.698, 6.407, and 5.441, and the proposed method calculates 0.990, 3.734, and 1.848 in recoil velocity, momentum and kinetic energy, respectively. In K100, the free recoil method demonstrates 1.190, 4.487, and 2.669, the gas exhaust aftereffect method computes 1.776, 6.699, and 5.949, and the proposed method calculates 1.060, 3.998, and 2.119 in recoil velocity, momentum and kinetic energy, respectively. Conclusion: This study implements live fire experiments to provide recoil velocity, momentum, and kinetic energy of K2 rifle using both M193 and K100 bullets. For the development of the army virtual reality marksmanship, the results in this paper would be useful to design and produce a gun and/or a rifle of virtual reality.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.4
• /
• pp.18-25
• /
• 2011

Solid propulsion systems have simple structures compared to other propulsion systems and are suitable for long-term storage. However the systems generally have limits on control of thrust levels. In this paper we suggest control algorithms for combustion chamber pressure of variable thrust solid propulsion systems using special nozzles such as pintle valve. For the pressure control within the chamber, we use a simple pressure change model by considering only mass conservation within the combustion chamber, design a classical algorithm and also a nonlinear controller using the feedback linearization technique. Also we derive the equation of the thrust for an under-expanded one-dimensional nozzle and then design a proportional-intergral controller after linearizing the thrust model for an operating point. Finally, we demonstrate the performance of the controller through a numerical simulation.

• Structural Engineering and Mechanics
• /
• v.4 no.5
• /
• pp.513-527
• /
• 1996

In this paper, both an approximate expression and an exact expression for the contribution factor of an element to the natural frequency of the finite element discretized system of a structure in general and a membrane in particular have been derived from the energy conservation principle and the finite element formulation of structural eigenvalue problems. The approximate expression for the contribution factor of an element is used to predict and determine the elements to be removed in an iteration since it depends only on the quantities associated with the old system in the iteration. The exact expression for the contribution factor of an element makes it possible to check whether the element is correctly removed at the end of an iteration because it depends on both the old system and the new system in the iteration. Thus, the combined use of the approximate expression and the exact expression allows a considerable number of elements to be removed in a single iteration so that the efficiency of the evolutionary structural optimization method can be greatly improved for solving the natural frequency optimization problem of a structure. A square membrane with different boundary supports has been chosen to investigate the general evolutionary path for the fundamental natural frequency of the structure. The related results indicated that if the objective of a structural optimization is to raise the fundamental natural frequency of the structure to an optimal value, the general evolutionary path during its optimization is that the elements are gradually removed along the direction from the area surrounded by the contour of the highest value to that surrounded by the contour of the lowest value.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.13 no.3
• /
• pp.183-189
• /
• 2007

In this paper, the strategic plan for Honam Sea Grant College Program will be discussed. The main activity area of Hanam SGCP is research and development, education and public information, outreach. Honam SG theme areas and priorities of its activity area will be determined to enhance the sustainable use and conservation of marine and fishery resources for Honam region. In the education and public information, marine education program executed by MOMAF and relative institutions is introduced and suitable program direction will be suggested. The network composition between HSGCP and other institution in domestic or abroad is also tackled. An interchange of beneficial information is accomplished through the effective network with other organizations. Finally the result of survey to develop the pending problems of Honam area will be discussed.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2008.10a
• /
• pp.201-206
• /
• 2008

Determining the coefficient of weathering(CW) for stone heritage plays very important role in investigation and conservation plan. In most case, CW is obtained from the empirical relation, which use the difference between sonic velocities of fresh and weathered rocks. In this paper, we measured sonic velocities for the samples from Iksan, Geochang, Wonju, Goesan and Chungju of which our stone heritages are made. We first investigate the uncertainty of velocity by portable measurement by comparing it to lab measurement. There were small difference, but we conclude that the difference is not major. However, the velocity of fresh rock differs significantly among samples: ranging from 3200 to 4400m/s. This cause a lot of error in CW estimation if we use typical fresh rock velocity as of 5000m/s. Thus accurate measurement of the velocity of fresh rock is crucial to CW estimation.

• The Korean Journal of Mycology
• /
• v.39 no.3
• /
• pp.155-163
• /
• 2011

The investigation on the species diversity for the Korean fungal flora was carried out by authors. Five species of the Agaricales recorded in the present paper are distributed Hygrocybe laeta (Pers.)P. Kummer var. laeta, Lyophyllum tylicolor (Fr.) M. Lange & Sivertsen, Clitopilus scyphoides (Fr.) Singer, var. scyphoides, Entoloma rusticoides (Gillet) Noordel. and Lactarius uyedae Singer were recorded for the first time and are described and illustrated in detail. Specimens cited here are deposited in the Herbarium Conservation Center of National Academy of Agricultural Sciences.

• Journal of the Korean association of regional geographers
• /
• v.10 no.4
• /
• pp.727-743
• /
• 2004

This paper aims to explore the geographic characteristics of ecotour resources in Gumho-river basin and to study the educational application of ecotour resources. To grasp the characteristics of ecotour resources in Gurnho-basin, this research carried out a literature review about Gumho-river basin and arranged ecotour resources by different types. Ecotour resources are divided into geomorphic and geologic resources, plant communities, wildlife habitats, cultural and historical resources, regional events with eco-resources. The case studies of New Zealand present good examples of how to successfully use the ecotour goals as a educational applications to Korea. The ecotourism in Korea has not still achieved the real benefits which meet environmental conservation, regional economic advantages and educational effects. Thus, the ecotour programmes should be include entrance limitations, strict opening time schedules, natural trails, museums for study, boards for study, well trained information officers and guides organized by residents. In addition, the local residents prepare of winter programmes for sustainable economic advantages.