• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.3
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• pp.166-176
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• 2003

Experiments have been conducted in order to make comparisons of a alternative refrigerant (R-410A) cycle characteristic with an existing refrigerant (R-22) cycle characteristic in terms of cooling capacity and coefficient of performance (COP). The parameters examined in the present work include air flow rate, indoor/outdoor air temperatures, and indoor relative humidity. These two refrigeration cycles share all components except compressor, accumulator, oil separator, and piping connecting them. The measurements were made using an air-enthalpy calorimeter. The experimental results show that the R-410A cycle has many advantages over indoor conditions while the R-22 cycle has better performance over outdoor conditions.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.107-114
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• 2023

In this paper, the results of experiments conducted in indoor wired and outdoor wireless environments to reduce the interference impact of 5G mobile communication on fixed satellite services using RF Interference Reduction Module (IRM) are presented. Test results for interference signals with a 100MHz bandwidth in a wired environment demonstrate that RF IRM can reduce interference by more than 20dB in a 100MHz bandwidth. The performance of RF IRM was also tested in the S-band wireless environments. In the S-band wireless environments with interference signals having a 20MHz bandwidth, RF IRM exhibits interference reduction performance of 12-15dB, for signals with a 50MHz bandwidth, it shows 10-12dB interference reduction, and for signals with a 100MHz bandwidth, it demonstrates 5-10dB interference reduction. This paper shows that RF IRM can be used not only within transceivers but also in wireless environments to mitigate interference.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.305-311
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• 1993

A total of thirty male Holstein calves were reared outdoors with simple housings or in warmed pens in three experiments conducted in three consecutive midwinters in Hokkaido. Average outdoor air temperatures during the experiments were between -5.3 and $-6.1^{\circ}C$, and average minimum air temperatures were between -9.7 and $-10.6^{\circ}C$. The age of calves at the start of the experiments were $16{\pm}6$ hours. There was no difference in the liquid feed intake, while the solid concentrate (artificial milk) intake by the calves in the simple housing systems (outdoors, calf hutch and open shed) tended to be higher than those in the warmed pen. No significant differences in the daily gain or the monthly development of wither height were observed among housing systems. There were no serious cases of diarrhea. However, coughing was observed in several of the calves reared in the poorly ventilated warmed pens.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.361-368
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• 1997

Summary of experiments for the investigation of a fire which caused an upward fire spread for over 12 floors through balconies in a high-rise apartment complex is reported. The experiments include indoor tests to obtain fire properties of vertical PMMA fences and outdoor ones with a full scale model of the balcony. The test results suggest significance of the increase of total flame height by the merging of flames and a cooperative effect of the burning of the PMMA fence and combustibles on the balconies for the generation of a tall flame enough to cause ignition on the upper floors.

• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1635-1640
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• 2017

In this paper, a hierarchical image tree model for weather classification is defined in a single outdoor image, and a weather classification algorithm using image intensity and k-mean segmentation image is proposed. In the first level of the hierarchical image tree model, the indoor and outdoor images are distinguished. Whether the outdoor image is daytime, night, or sunrise/sunset image is judged using the intensity and the k-means segmentation image at the second level. In the last level, if it is classified as daytime image at the second level, it is finally estimated whether it is sunny or foggy image based on edge map and fog rate. Some experiments are conducted so as to verify the weather classification, and as a result, the proposed method shows that weather features are effectively detected in a given image.

• Journal of Korea Water Resources Association
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• v.56 no.7
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• pp.461-470
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• 2023

The purpose of this research is to derive the optimal temperature, location, and heating control system for a tipping bucket rain gauge heating system used for observing snowfall during winter. We conducted indoor and outdoor experiments by manufacturing a tipping bucket rain gauge that can be variably controlled for heating at the funnel, exterior, and interior, and indoor and outdoor. The indoor experiments involved using a temperature and humidity chamber to compare the performance and derive the appropriate temperature of the precipitation gauge heating system. Subsequently, the outdoor experiments were carried out at the Cloud Physics Observation Center located in Daeguallyeong, heavy snowfall region, to validate the findings. The analysis result was derived that the heating temperature of the funnel should be set at the 10 to 30℃, while the internal heating temperature should be 70℃. Furthermore, the optimal locations for the heating devices, which aim to minimize measurement delay, were identified as the exterior of the rain gauge, the rim of the funnel, and the vertical surface of the funnel. Our result shows that used as the basis for the operating conditions of precipitation gauge heating systems for solid precipitation measurement in winter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.593-598
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• 2018

Computational fluid dynamics was used to develop a heat-recovery ventilator for preventing freezing in cold weather. An optimal internal return damper was applied, and a prototype was made for frost and freezing experiments. A total of 16 models were used to design the optimal internal return damper with the maximum exhaust recirculation ratio. The exhaust recirculation ratio of the exhaust air to the outdoor air was 59.9-62.3%. The tests showed that frost and freezing did not occur at outdoor air temperatures of $-15^{\circ}C$ or higher in both exhaust recirculation operation and normal operation. However, at an outdoor air temperature of $-20^{\circ}C$, no freezing occurred in the outdoor air area when the internal return damper was opened by 45 degrees. Heat recovery ventilators for preventing cold weather frost and freezing should be operated in two operation modes: normal and exhaust recirculation mode. An operating algorithm was developed for the heat-recovery ventilator operating in normal mode when the outdoor temperature is higher than $-15^{\circ}C$ and recirculation mode when the temperature is lower.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.953-954
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• 2008

Wireless Sensor Network (WSN) surveillance applications usually employed magnetometer for recognizing the ferrous objects. Novel magnetic sensing model which includes azimuth parameter is suggested to understand the anisotropic characteristic of magnetic field through numerous outdoor experiments.

• ALGAE
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• v.33 no.4
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• pp.359-366
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• 2018

Mesocosm experiments conducted for ecological purposes have become increasingly popular because they can provide a holistic understanding of the biological complexities associated with natural systems. This paper describes a new outdoor mesocosm designed for $CO_2$ perturbation experiments of benthos. Manipulated the carbonate chemistry in a continuous flow-through system can be parallelized with diurnal changes, while irradiance, temperature, and nutrients can vary according to the local environment. A target hydrogen ion activity (pH) of seawater was sufficiently stabilized and maintained within 4 h after dilution, which was initiated by the ratio of $CO_2$-saturated seawater to ambient seawater. Specifically, pH and $CO_2$ partial pressure ($pCO_2$) levels gradually varied from 8.05-7.28 and $375-2,691{\mu}atm$, respectively, over a range of dilution ratios. This mesocosm can successfully manipulate the pH and $pCO_2$ of seawater, and it demonstrates suitability for ocean acidification experiments on benthic communities.

• The Journal of Korea Robotics Society
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• v.2 no.4
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• pp.353-360
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• 2007

This paper proposes the trot gait pattern generation and online control methods for a quadruped robot to carry heavy loads and to move fast on uneven terrain. The trot pattern is generated from the frequency modulated pattern generation method based on the frequency modulated oscillator in order for the legged robots to be operated outdoor environment with the static and dynamic mobility. The efficiency and performance of the proposed method are verified through computer simulations and experiments using qRT-1/-2. In the experiments, qRT-2 which has two front legs driven by hydraulic linear actuators and two rear casters is used. The robot can trot at the speed up to 1.3 m/s on even surface, walk up and down the 20 degree inclines, and walk at 0.7 m/s on uneven surface. Also it can carry over 100 kg totally including 40 kg payload.