• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.773-782
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• 2007

The statistical process control charts are very extensively used for monitoring of process mean, deviation, defect rate or reject rate. In this paper we consider a control chart to monitor the process reject rate in the high yield process, which is based on the observed cumulative probability of the number of items inspected until r defective items are observed. We first propose selection of the optimal value of r in the CPC-r charts, and also consider the usefulness of the chart in high yield process such as semiconductor or TFT-LCD manufacturing process.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.234-240
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• 2016

Energetically-modified material using reject fly ash (RFA), generated from thermal power plants, was manufactured to investigate the effect of the material on the physical and chemical characteristics of cement mortar. In order to modify reject fly ash, a vibration mill was used. Particle size, grain shape, and crystal structure of the ash were analyzed. Then, the compressive strength of the mortar using energetically-modified reject fly ash (ERFA) was measured. Microstructure and X-ray diffraction (XRD) patterns were also used in the analysis. As the replacement rate of ERFA increased, the value of the compressive strength tended to decrease. However, it was found that the compressive strength values of 7 and 28 days-cured specimens were higher than those of conventional ordinary Portland cement (OPC) mortar with 10 % replacement rate condition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.158-163
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• 2012

The purpose of this study is to improve recycling rate of the coal reject ash by investigating bloating mechanism for artificial lightweight aggregate of reject ash. In this study, we use reject ash (R/A) and dredged soil (D/S) as raw materials. The artificial lightweight aggregates were formed by plastic forming (${\phi}$ = 10 mm) and sintered by temperature raising method at different temperatures (between 1200 and $1275^{\circ}C$). The physical properties of the aggregates such as bulk specific gravity, adsorption and microstructure of surface and cross-section are investigated with the sintering temperature and rate of R/A-D/S contents. As the result of the bulk specific gravity graphs, we can found out the inflection point at content of R/A 80 wt.%. From the microstructure images, we considered the artificial lightweight aggregates content of R/A over 80 wt.% are distributed numerous uniform micro-pores by vitrification without Black Core and the artificial lightweight aggregates of R/A below 80wt.% are distributed macro-pores with Black Core.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.261-264
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• 2003

얼굴인식은 동일 사람의 얼굴이라도 조명변화나 얼굴 표정변화에 따라 매우 다른 영상들로 나타나기 때문에 매우 어려운 문제이다. 본 논문에서는 조명변화에도 강인하고 얼굴영상에 대해 높은 얼굴 인식률을 얻기 위해 2D-HMM(Hidden Markov Model) 얼굴인식 방법을 제안하고 실험하였다. 제안된 방법은 조명변화에 대해서 조명변화 함수인 $\delta$(delta) 함수를 0, 40, 60, 80으로 변화해 가면서 이미지 보정을 실험하였으며, 계산의 복잡성을 줄이고 얼굴영상에 대한 높은 인식률을 얻기 위해 기존의 픽셀값 대신에 2D-DCT 계수를 관측벡터로 사용하였다. 시스템의 성능을 평가하기 위해 정량적 평가방법은 FAR(False Accpt Rate)와 FRR(False Reject Rate)를 측정하여 비교하였으며, 기존의 얼굴인식 방법인 PCA, 1차원 HMM과 비교분석하였다. 실험결과 2D-HMM의 경우 FAR(False Accept Rate)가 5.08%로 ID-HMM 5.18%, PCA 10.16%보다 높은 성능을 보였으며, FRR(False Reject Rate)의 경우에도 0.01%로 10.16%인 PCA보다 좋은 성능을 보였다. 이로서 조명변화에 대해서는 PCA보다 2D-HMM 얼굴인식 방법이 우수함을 알 수 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.201-206
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• 2013

The coal bottom ash and reject ash discharged from a coal-fired power plant are difficult to recycle so most of them are mainly landfill-disposed. In this study, the artificial aggregate were produced using reject ash, bottom ash and dredged soil emitted from the coal-fired power plant in Korea and the effect of experimental factors on the bloating behavior and the properties of the aggregates were analyzed. In particular, a lot of unburned carbon in the reject ash was removed by calcination and the activated carbon was added to batch powders then the dependence of those process upon bloating properties of artificial aggregate were investigated. For this purpose, the specific gravity and water absorption values of artificial aggregates were investigated in conjunction with microstructural observations. This study could contribute to increase the recycling rate of the reject ash.

• Journal of the Korean Ceramic Society
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• v.49 no.2
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• pp.161-166
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• 2012

The temperature-rasing sintering method was used in this study to fabricate the aggregates of uniform pore size and distribution containing reject ash occurred in the thermal power plant. The spheric green aggregates made of reject ash were put into the box furnace of 800~$1000^{\circ}C$, heated with a heating rate of 5~$15^{\circ}C$/min to 1200~$1275^{\circ}C$, sintered for 10 min and then discharged out of the furnace to the room temperature. The input temperature, heating rate and sintering temperature increased the bloating phenomenon of the specimen, and the sintering temperature among them was the most effective factor. The aggregate manufactured at $1275^{\circ}C$ had the specific gravity of about 1.0 and water absorption of 1~2%, and the pores of 500~1,000 ${\mu}m$ were uniformly distributed across the whole specimen. Especially, the aggregates fabricated using the temperature-rasing sintering method in this study showed an excellent bloating properties and uniform microstructure without black core phenomenon which is typical for the bloated ceramics synthesized by direct sintering method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.81-84
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• 2000

Rotating machine is used extensively and plays important roles in the industrial field. Therefore when rotating machine get out of order, it is necessary to know reasons then deal with the troubles immediately. So many studies far diagnosis of rotating machine are being done. However by this time most of study has an interest in gaining a high recognition But without considering error $rate^{(1)(2)(3)}$ , it is not desirable enough to apply h the actual application system. If the manager of system receives the result misjudging the condition of rotating machine and takes measures, we would lose heavily. So in order to play the creditable diagnosis, we must consider error rate. T h ~ t is. it must be able to reject the result of misjudgment. This study uses nearest neighbor classifier for diagnosis of rotating $machine^{(4)(8)}$ And the Smith's rejection $method^{(1)}$ used to recognize handwritten charter is done. Consequently creditable diagnosis of rotating machine is proposed.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.91-95
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• 2012

The photoplethysmography (PPG) signal measured from a mobile healthcare device contains various motion artifacts occurring from a patient’s movements. Recently, to reject the motion artifacts, the method of using an acceleration sensor was suggested, but such sensors are very expensive. Therefore, this study deals with a novel sensor device to replace the acceleration sensor, and evaluated the performance of the proposed sensor experimentally. In the results of the experiments, it is shown that the proposed sensor device can reconstruct the PPG signal despite the occurrence of motion artifacts, and also that the variation rate in heart rate analysis was 1.22%. According to the experimental results, the proposed method can be applied to design a low-cost device.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.265-275
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• 2019

This study aimed to develop a compact partial nitritation step by forming granules with high Ammonia-Oxidizing Bacteria (AOB) fraction using the Air-lift Granulation Reactor (AGR) and to evaluate the feasibility of treating reject water with high ammonium content by combination with the Anammox process. The partial nitritation using AGR was achieved at high nitrogen loading rate ($2.25{\pm}0.05kg\;N\;m-3\;d^{-1}$). The important factors for successful partial nitritation at high nitrogen loading rate were relatively high pH (7.5~8), resulting in high free ammonia concentration ($1{\sim}10mg\;FA\;L^{-1}$) and highly enriched AOB granules accounting for 25% of the total bacteria population in the reactor. After the establishment of stable partial nitritation, an effluent $NO_2{^-}-N/NH_4{^+}-N$ ratio of $1.2{\pm}0.05$ was achieved, which was then fed into the Anammox reactor. A high nitrogen removal rate of $2.0k\; N\;m^{-3}\;d^{-1}$ was successfully achieved in the Anammox reactor. By controlling the nitrogen loading rate at the partial nitritation using AGR, the influent concentration ratio ($NO_2{^-}-N/NH_4{^+}-N=1.2{\pm}0.05$) required for the Anammox was controlled, thereby minimizing the inhibition effect of residual nitrite.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.199-204
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• 2015

In this study, prevention methods of radial cracks generated inside of artificial lightweight aggregate made of reject ash and dredged soil were investigated. The reject ash and dredged soil had mixed with weight ratio of 7 : 3 and formed to spheric shape of 5~20 mm diameter, then, the aggregates were manufactured using flash sintering method at $1200^{\circ}C$ for 10 min. The formation of radial cracks in the aggregates were suppressed as the size of specimen decreased. Also, the addition of silica to aggregates had prevented generation of the radial cracks. As the size and the amount of silica powder added increased, the development of radial cracks was constrained. Therefore the artificial lightweight aggregate manufactured in this study expected to be applicable to many fields such as construction and environmental usages. Also it is expected to contribute greatly to increase the recycling rate of reject ash and dredged soil.