• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.328-331
• /
• 2001

Shape changes of a workpiece in an Eulerian Finite Element analysis for the steady state. three-roll-stand shape rolling are modelled. Although an Eulerian analysis has many advantages for the steady state rolling problems, it necessitates an assumption about the unknown shape of the control volume. In almost all cases. the assumed control volume does not match the final shape and the control volume should be updated. This update can be accomplished by performing a free surface correction. The final shape of a material point, which has a spherical shape at the inlet, can be also predicted by integrating a deformation gradient along a stream line. Analyses of three-roll-stand shape rolling is in detail examined.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 F
• /
• pp.2626-2627
• /
• 1999

The device we have developed is the automatic shut off equipment which will reduce energy consumption when an equipment is in stand by power state. The principle for this system is when a man is moving, electricity will flow by setting a on-off light system. At night, in the stand-by power state the electric supply will be shut off immediately which will reduce energy consumption. Energy consumed by 24hour operating machines and stand-by electronic devices will be reduced by pulse signals which will give power supply when needed.

• The Korean Journal of Ecology
• /
• 제6권2호
• /
• pp.90-97
• /
• 1983

Seasonal changes of the soil nutrient contents and aboveground biomass, relationship between the soil nutrients and the productivity, and the net efficiencies of solar energy conversion were studied in two reeed communities (Phragmites communis Trin.) at the salt marsh in the estuary of the Sumjin-River from April 30 to October 9, 1981. The inorganic nutrients such as exchangeable sodium and potassium of soil were decreased during growing season. The amounts of organic matter, exchangeable sodium and potassium, total nitrogen, and available phosphorus in stand $\prod$ were much more than those of stand $\coprod$ . Productivity of Phragmites communis was positively correlated with the soil nutrients such as available phosphorus, exchangeable potassium and total nitrogen. The maximum dry matter productions of the aboveground parts in stand $\prod$ stand $\coprod$ were $ 1, 120g/m^2; and; 843g/m^2$ in August, and the net coversion efficiencies of PhAR based on growing season (April to September) were 1.77% and 1.33%, respectively.

• 자동차안전학회지
• /
• 제10권1호
• /
• pp.6-11
• /
• 2018

Recently, many drivers of two-wheeled motorcycles in leisure and express delivery industries etc. brought increasing issues for the motorcycle safety. This paper has studied the structural safety of two-wheeled motorcycles considering the regulations for stand, rear registration plate and anti-tampering measures. The authors have investigated and compared a variety of international and domestic regulations and specifications for structural safety of those components. Detailed experimental procedures of stand, mounting for rear registration plate and anti-tampering measures are proposed to secure the two-wheeled motorcycle safety and the outcomes of this study can be used to confirm the Korean motor vehicle safety standards.

• 한국정밀공학회지
• /
• 제33권11호
• /
• pp.937-941
• /
• 2016

Stand-alone cervical cage consists of a PEEK body, Ti plate, and screw, which are configured as a single-piece. Through a single operation, this implantable medical device is capable of completely fixing the cervical vertebral body. For example, instead of a plate, which is normally used, the intervertebral disc is removed and replaced with a cervical cage. It should be noted that in Korea, KFDA guidelines for a stand-alone cervical cage have not yet been suggested. Therefore, the aim of this study is to present the systematic study of the static compression test, static torsion test, dynamic compression test, and expulsion test. Further, the test method is designed to refer to the ASTM standard and relative literature.

• 한국정밀공학회지
• /
• 제19권9호
• /
• pp.133-141
• /
• 2002

In this paper, we propose a hierarchical motion controller with stand-alone vision system to enhance the flexibility of the robot soccer system. In addition, we simplified the model of dynamic environments of the robot using petri-net and simple state diagram. Based on the proposed model, we designed the robot soccer system with velocity and position controller that includes 4-level hierarchically structured controller. Some experimental results using the stand-alone vision system from host system show improvement of the controller performance by reducing processing time of vision algorithm.

• 환경생물
• /
• 제20권4호
• /
• pp.287-293
• /
• 2002

원시림이 없는 한국에 산림생태계 이해에 근원이 될 자연림은 매우 중요한 의미를 가진다. 설악산에 존재하는 몇몇 전나무 고목림의 자연성을 판단하기 위하여 국제적으로 통용되는 원시림 혹은 자연림의 특징과 임분 동태학을 산림생태계 변화(천이)의 기본으로 상정하고 조사를 진행하였다. 비록 면적은 좁지만 모든 조사지역은 자연성을 확실히 보이고 있으며 수진된 기초자료는 한국 자연림 연구의 밑거름이 되리라 사료된다.

• 한국환경복원기술학회지
• /
• 제10권6호
• /
• pp.62-69
• /
• 2007

This study has been carried out to estimate aboveground carbon contents in an average 30-years-old Betula platyphylla and 32-years-old Juglans mandshurica stands in Chungju, Chungbuk Province. Nine sample trees were cut in each forest and soil samples were collected. Carbon concentration in stemwood, stembark, branch, and foliage were ranged from 54.6% to 57.0% in Betula platyphylla and 53.5% to 56.9% in Juglans mandshurica stands. Aboveground carbon contents was estimated by the equation model logWt=A+BlogD where Wt is oven-dry weight in kg and D is DBH in cm. Total aboveground carbon contents was 34.31t/ha in Betula platyphylla stand and 21.10t/ha in Juglans mandshurica stand. Aboveground net primary carbon production was estimated at 2.31t/ha/yr in Betula platyphylla stand and 2.03t/ha/yr in Juglans mandshurica stand.

• 전기학회논문지
• /
• 제64권8호
• /
• pp.1168-1179
• /
• 2015

This paper presents voltage and frequency control methods for a stand-alone Gasa Island Microgrid in South Korea that can be fully energized by renewable energy resources such as photovoltaic systems and wind turbines. To mitigate the variations of the output of renewable energy resources and supply more reliable electricity to customers, battery energy storage systems (BESSs) are employed in the stand-alone microgrid. The coordination between BESSs and pre-existing diesel generators is an important issue to manage the microgrid more securely. This paper presents voltage and frequency control schemes considering the coordination of BESSs and DGs. The effectiveness for the operating method is validated via simulation studies.

• 전기학회논문지
• /
• 제58권2호
• /
• pp.239-241
• /
• 2009

In this paper, an estimation methodology for stand-by energy savings of electric appliances is proposed and some case studies are carried out for televisions. The methodology is based on learning curves and diffusion models, which are able to explain the market characteristics such as market prices and the diffusion speed. Some models were developed to estimate power and energy savings for high-efficient appliances and these model have been used broadly. These models are also applied to this study and modified to estimate stand-by energy savings.