• Journal of The Korean Society of Agricultural Engineers
• /
• v.56 no.3
• /
• pp.39-45
• /
• 2014

Dust is mostly caused by human activity. The effect of natural factors on dust emission were studied in many research, but the little effort in researching artificial factors of dust emission. The object of study is to analysis dust emission characteristic by drop impact. Particle matter $10{\mu}m$ ($PM_{10}$) was measured by drop impact on paved soil with changing drop height, weight and drop size. Increasing drop height cause more $PM_{10}$ emission. Increasing drop weight cause more $PM_{10}$ emission but had limit weight for increasing dust emission. Because the exceed kinetic energy of drop weight penetrate the soil surface. The limit perimeter was exist that separating $PM_{10}$ emission aspect. Under limit perimeter, $PM_{10}$ emission was increasing while perimeter was increasing, but over limit perimeter showed the opposite aspect. Regression equations for estimating $PM_{10}$ with kinetic energy and perimeter were made under limit perimeter and over limit perimeter. The $R^2$ of those equations were 0.784, 0.743. The error has occurred between measured $PM_{10}$ and calculated $PM_{10}$ in the equation under limit perimeter. But using equation of case for over limit perimeter, PM10 can be estimated with kinetic energy and drop perimeter.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.5
• /
• pp.346-351
• /
• 2003

This paper aims at suggesting design guidelines for a perimeter-less HVAC system that contributes energy savings. Perimeter-less HVAC system is one that relieves difficulties fuck as handling mixing loss, uneven radiative environment, and maintenance and repair. It prevents heat load gained through window and outdoor wall without modifying a previously equipped building skin system. In this paper, we performed several kinds of CFD (computational fluid dynamics) cases through numerical simulation to obtain an optimized perimeter-less design, and then we conducted a large-scale model experiment to see how the push-pull air flow would handle indoor heat to obtain an optimized perimeter-less design.

• Journal of the Korean Solar Energy Society
• /
• v.30 no.2
• /
• pp.33-38
• /
• 2010

The perimeter zone is space which receives a significant effect of ambient condition, it is necessary to improve the thermal performance in order to building energy saving. For this reason, a lot of study about the active approach is being performed, such as perimeter-less air conditioning system. But the performance of the perimeter zone is necessary to improve, through the passive approach. Therefore, the purpose of this study is to provide basic materials of energy-saving design of perimeter zone, based of the PAL that simulation changing the thickness of insulation and the rate of windows.

• Journal of the Korean Mathematical Society
• /
• v.41 no.2
• /
• pp.397-406
• /
• 2004

For a Boolean rank-l matrix $A\;=\;ab^{t}$, we define the perimeter of A as the number of nonzero entries in both a and b. We characterize the Boolean linear operators that preserve rank and perimeter of Boolean rank-l matrices.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 2004.11a
• /
• pp.195-199
• /
• 2004

The purpose of this study is to grasp the foundation and development of perimeter block housing in Berlin. The results of this study is as follows : Perimeter block housing in Berlin have been developed from small laborer house to gradually large- scale housing. The court used for natural lighting and draft, have been developed to a space for resident community or individual garden.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.11
• /
• pp.25-31
• /
• 2009

In this paper we propose an improved energy aware greedy perimeter stateless routing protocol (EAGPSR) for wireless ad hoc network. The existing greedy perimeter stateless routine (GPSR) has some problems with overloaded node and void situation. The improved EAGPSR protocol is proposed to remedy these problems. It also gives the solution for the fundamental problem in geographical routine called void communication. It considers two parameters (Residual Energy of battery and distance to the destination) for the next hop selection. In order to use efficiently limited-energy of node in wireless ad hoc network, network lifetime is focused. To evaluate the performance of our protocol we simulated EAGPSR in ns-2. The simulation results show that the proposed protocol achieves longer network lifetime compared with greedy perimeter stateless routing (GPSR) and the existing Energy aware greedy perimeter stateless routing protocol (EAGPSR).

• 한국연소학회:학술대회논문집
• /
• 2005.10a
• /
• pp.314-319
• /
• 2005

In this study, the combustion characteristics were investigated with the variation of design factors on multiple slit gas burner. The design factors consist of slit height, width, spacing, and inner length. The combustion characteristics were made analysis of the CO emission and NOx emission by using CO analyzer and NOx analyzer. The lower perimeter to area and the narrow spacing extends the lift-flame limit. The CO emission increases with the increasing perimeter to area ratio at the same condition. The NOx emission is found to be less significant with the port perimeter to area ratio. The flame interference might highly depend on the spacing and port perimeter to area ratio, and it also affects the burner performance.

• Honam Mathematical Journal
• /
• v.39 no.1
• /
• pp.127-136
• /
• 2017

For a quadrangle P, we consider the centroid $G_0$ of the vertices of P, the perimeter centroid $G_1$ of the edges of P and the centroid $G_2$ of the interior of P, respectively. If $G_0$ is equal to $G_1$ or $G_2$, then the quadrangle P is a parallelogram. We denote by M the intersection point of two diagonals of P. In this note, first of all, we show that if M is equal to $G_0$ or $G_2$, then the quadrangle P is a parallelogram. Next, we investigate various quadrangles whose perimeter centroid coincides with the intersection point M of diagonals. As a result, for an example, we show that among circumscribed quadrangles rhombi are the only ones whose perimeter centroid coincides with the intersection point M of diagonals.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.11
• /
• pp.970-978
• /
• 2003

This paper aims at suggesting design guidelines for a perimeter-less HVAC system that contributes energy savings. Perimeter-less HVAC system is one that relieves difficulties such as handling mixing loss, uneven radiative environment, and maintenance and repair. It prevents heat load gained through window and outdoor wall without modifying a previously equipped building skin system. In this paper, we conducted a large-scale model experiment to see how the push-pull air flow would handle indoor heat to obtain an optimized perimeter-less design, and then we plan to perform several kinds of CFD (computational fluid dynamics) cases through numerical simulation

• Education of Primary School Mathematics
• /
• v.6 no.2
• /
• pp.85-91
• /
• 2002

The purpose of this study is to analyze elementary students' understanding the relationship between perimeter and area in geometric figures. In this study, the questionaries were used. In the survey, the subjects were elementary school students in In-cheon city. They were 86 students of the fifth grade, 86 of the sixth. They were asked to solve the problems which was designed by the researcher and to describe the reasons why they answered like that. Study findings are as following; Students have misbelief about the concept of the relationship between perimeter and area in geometric figures. Therefore, 1 propose the method fur teaching about the relationship between perimeter and area in geometric figures. That is teaching via problem solving.. In teaching via problem solving, problems are valued not only as a purpose fur learning mathematics but also a primary means of doing so. For example, teachers give the problem relating the concepts of area and perimeter using a set of twenty-four square tiles. Students are challenged to determine the number of small tiles needed to make rectangle tables. Using this, students can recognize the concept of the relationship between perimeter and area in geometric figures.