• 한국위성정보통신학회논문지
• /
• 제10권4호
• /
• pp.12-16
• /
• 2015

무인로봇체계는 미래전이라 불리우는 네트워크 중심전의 핵심기술이라 할 수 있다. 그러나, 인프라 기반의 무선통신시스템과는 다른 야전 환경에서 안정된 통신을 유지하는 것은 상당한 링크 버짓을 요구한다. 따라서, 기지국과 단말 사이의 불안정한 채널이 형성될 경우 무선링크의 장애를 최소화하기 위한 방법이 필요하다. 본 논문에서는 야전 환경에 투입되는 무인로봇 체계를 통해 확보되는 전장에서의 정보를 효과적으로 송수신하도록 하며 통신환경이 열악한 상태에서도 무인로봇의 제어권을 잃지 않도록 하는 즉, 통신생존성을 보장하도록 하는 알고리즘을 제안한다. 본 논문에서 제안하는 시스템의 성능분석을 위해 실제 국내의 산악지방, 개활지 등과 유사한 채널을 적용하였으며, 향후 무인로봇체계에 활용할 수 있도록 한다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.115-116
• /
• 2023

This study aims to investigate and improve the carbon dioxide sequestration capability and the mechanical properties of non-hydraulic low calcium silicate cement especially designed for CO₂ reaction and ordinary Portland cement subjected to the carbonation curing facilitating pH swing method. Nitric acid (HNO₃) was utilized as an liquid for the mixing of cement paste to enhance the initial dissolution of Ca ions from the cements by promoting low pH environment and prevent the direct precipitation of Ca with the anion, owing to the high solubility of Ca(NO₃)₂ in water. The results presented that the higher the concentration of HNO₃, the higher the compressive strength and CO₂ sequestration (until 0.1 M). Ca dissolution caused by the harsh acid attack onto the anhydrous cement particle lead to the higher carbonation reaction degree, forming abundant CaCO₃ crystals after the reaction. However, cement paste mixed with excessively high concentration of HNO₃ presented deterioration due to the too harsh pH environment and abundant NO₃- ions which are known to retard the reaction of cement.

• 한국생물환경조절학회:학술대회논문집
• /
• 한국생물환경조절학회 2000년도 학술발표논문집
• /
• pp.3-16
• /
• 2000

Protection agriculture is the essential choice for human to increase the efficiency of limited crop production area under harsh and changeable weather boundary conditions, extend growing season, maximize the crop yields, and then increase the sustainable income of the grower. The investment costs far greenhouses as well as labor and energy costs are much higher than for conventional plant production systems, so these can only be balanced by better crop yields, higher labor productivity, and higher energy efficiency. (omitted)

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2022년도 가을 학술논문 발표대회
• /
• pp.241-242
• /
• 2022

Recently, related studies on the application of bacterial spores to self-healing concrete have been widely reported. Using the self-healing method of bacterial spores as a kind of pro-environment, the green method is very attractive, but because the living environment of bacterial spores is relatively harsh, it is necessary to have a way to separate the living environment of bacterial spores from the harsh external environment, And release bacterial spores when needed. Therefore, capsules are widely used in self-healing concrete. To enhance the self-healing effect, the capsules need to be evenly distributed in the concrete. Furthermore, we develop a CIP-based smart capsule with controllability. We determined the magnetic force of each capsule by mixing CIP in resin, then mass-fabricating the capsules for self-healing by a microfluidic method, and by measuring the kinetic distance of the capsules containing different amounts of cip under the action of a magnetic field strength. The results show that with the increase of the amount of cip, the active distance of the capsule also increases. When the cip is 8wt%, the active distance reaches 1.75cm. We believe this research can provide momentum for the development of self-healing capsule applications.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 춘계학술대회논문집
• /
• pp.1772-1777
• /
• 2000

The Combat Computer Consoles installed in surface ships should endure harsh environment such as vibration from engine or propeller and shock from underwater explosion. Generally, commercial isolation mounts are selected and used for anti-vibration and anti-shock design. In this research, the environment of the Combat Computer Console was analyzed first. Selected proper mount was modeled and computer simulation was performed to emulate the environment test. The real environment test was conducted with a manufactured Combat Computer Console. The test results were same as the simulation and satisfied the performance requirements. The computer simulation proved to be a useful design tool to predict the performance before the final environment test.

• Journal of Ecology and Environment
• /
• 제44권3호
• /
• pp.162-177
• /
• 2020

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon-Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research.

• 해양환경안전학회지
• /
• 제24권3호
• /
• pp.360-366
• /
• 2018

In shipyards hull forming is performed by the line heating method using a gas torch and by cold treatment using a roll-press. However, this forming process has some issues, such as difficulties in controlling and accurately estimating the amount of the heat input, as well as a harsh working environment due to exposure to loud noises and air pollution. The induction heating method, which is introduced in this paper, exhibits good control and allows for the estimation of precise heat input. Also, workers can carry out the induction heating in a comfortable working environment. In this research, the induction heating simulation, which consists of electro-magnetic, heat transfer and thermal elasto-plastic analysis, was developed and modified through induction heating experiments. Finally, the effective heating coil was designed for the automatic hull forming system based on the results of induction heating simulation. For the purposes of a future study, if an algorithm to obtain optimal working conditions is developed, automatic systems for hull forming can then be constructed.

• 한국제4기학회지
• /
• 제16권2호
• /
• pp.39-56
• /
• 2002

The results of geoarchaeological studies of the prehistoric cultural complexes on the Russian Far East (Primorye, or Maritime Province; the Amur River basin; and Sakhalin Island) are presented. Upper Palaeolithic sites are dated to ca. 40,000-10,500 B.P. They existed during the mild climate of the Chernoruchie interstadial (ca. 40,000-21,000 B.P.); during harsh climate at the Last Glacial Maximum, ca. 20,000-18,000 B.P., in several places on the Russian Far East (Primorye, Amur River basin, and Sakhalin); and during climatic amelioration in the Late Glacial time, ca. 16,000-10,500 B.P. The earliest Neolithic sites, represented by Osipovka and Gromatukha cultures, existed at ca. 13,000-10,000 B.P. in the environment of coniferous forests with admixture of broadleaved taxa. Since ca. 8000 B.P., Neolithic cultures appeared in all of the Russian Far East. They existed until ca. 3000 B.P., first during the Holocene Climatic Optimum, ca. 8000-5000 B.P., in the environment of coniferous-broadleaved forests, and later, at ca. 5000-3000 B.P., in the environment of birch-oak and coniferous forests.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.3039-3045
• /
• 2023

Fiber-reinforced polymer (FRP) composites are considered suitable candidates for structural materials of spacecrafts due to their excellent properties of high strength, light weight, and corrosion resistance. An online health monitoring method for FRP composites must be applied to space structures. However, the application of existing health monitoring methods to space structures is limited due to the harsh space environment. Here, carbon fiber-reinforced polymer (CFRP) composites embedded with fiber Bragg grating (FBG) sensors were prepared to explore the feasibility of strain monitoring using embedded FBG sensors in γ-radiation environment. The analysis of the influence of radiation on the strain monitoring demonstrated that the embedded FBG can be successfully applied to the health monitoring of FRP composites in radiation environment.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 하계학술대회 논문집 F
• /
• pp.2129-2131
• /
• 1997

A sensorless controller of induction motor has several advantage: availability in a harsh environment. In this paper, the speed information is driving from the currents and the estimated stator flux. To obtain the estimated stator flux, this study is using The Estimator. The simulation results show that the proposed scheme has activity over a wide speed range and good response to load variations