• Journal of the Korean Statistical Society
• /
• 제29권3호
• /
• pp.319-336
• /
• 2000

A mixed model with a white noise process and an IMA(0,1,1) process is considered as a process model. It is assumed that the process is a white noise in the absence of a special cause and the process changes to an IMA(0,1,1) due to a special cause. One useful scheme in measuring the process level is to use the variable measurement interval (VMI) between measurement times according to the value of the previous chart statistic. The advantage of the VMI scheme is to measure the process level infrequently when in control to save the measurement cost and to measure frequently when out of control to save the off-target cost. This paper considers the VMI scheme in order to detect changes in the process model from a white noise to an IMA(0,1,1). The VMI scheme is shown to be effective compared to the standard fixed measurement interval (FMI) scheme in both statistical and economic contexts.

• Journal of the Korean Data and Information Science Society
• /
• 제21권6호
• /
• pp.1311-1317
• /
• 2010

A continuous time asymmetric power GARCH(1,1) model is suggested, based on a single background driving L$\'{e}$vy process. The stochastic differential equation for the given process is derived and the strict stationarity and kth order moment conditions are examined.

• 상하수도학회지
• /
• 제21권4호
• /
• pp.375-383
• /
• 2007

Treatment efficiency research was performed using Fenton process and the electrochemical process in the presence of ferrous ion and hydrogen peroxide for the industrial wastewater including 1,4-Dioxane produced during polymerization of polyester. The Fenton process and the electrochemical Iron Redox Reaction (IRR) process were applied for this research to use hydroxyl radical as the powerful oxidant which is continuously produced during the redox reaction with iron ion and hydrogen peroxide. The results of $COD_{Cr}$ and the concentration of 1,4-Dioxane were compared with time interval during the both processes. The rapid removal efficiency was obtained for Fenton process whereas the slow removal efficiency was occurred for the electrochemical IRR process. The removal efficiency of $COD_{Cr}$ for 310 minutes was 84% in the electrochemical IRR process with 1,000 mg/L of iron ion concentration, whereas it was 91% with 2,000 mg/L of iron ion concentration. The lap time to remove all of 1,4-Dioxane, 330 mg/L in the wastewater took 150 minutes with 1,000 mg/L of iron ion concentration, however it took 120 minutes with 2,000 mg/L of iron ion concentration in the electrochemical IRR process.

• 수산해양기술연구
• /
• 제52권3호
• /
• pp.271-275
• /
• 2016

Recently, pollution problem in coastal water has become more serious and pollution including red tide serves as a main reason for reduction of fishes resources. Particularly, nutrients such as nitrogen and phosphorus are the most serious pollutants. Normally, biological wastewater treatment process is used in removing such nutrients. However, it is difficult to adopt the biological wastewater treatment process to a small-scale fish processing factory in case of using seawater as wash water. Thus, removing nutrients through struvite crystallization is investigated in this study for treating shrimp processing wastewater. Experiments were conducted by varying molar ratio of $Mg^{2+}:NH^4-N:PO^4-P$ from 1:1:1 to 2:1:1. It can be concluded that optimum molar ratio is 1:1:1. Struvite crystallization process is compared with chemical coagulation process using PAC and struvite crystallization process is proven as the more effective process in removing nutrients from wastewater. In view of results obtained from these experiments, struvite crystallization process is a promising method in removing nitrogen and phosphorus from wastewater; however, not so good in removing organics. Thus, struvite crystallization process is suitable as the pre-treatment process in treating shrimp processing wastewater and additional biological process is needed to remove organics.

• 응용통계연구
• /
• 제16권1호
• /
• pp.71-85
• /
• 2003

일정 시간간격으로 품질을 측정하는 공정관리절차의 경제적 설계에서는 그 특성의 규명이 측정시점의 이산성 (discreteness) 때문에 복잡하고 어렵다. 이 논문에서는 공정 탐색 절차를 Markov 연쇄(chain)로 표현하는 과정을 개발하였고, 공정분포가 공정주기 내에서 발생하는 잡음과 이상원인의 효과를 설명할 수 있는 ARIMA(0,1,1) 모형을 따를 때에 Markov 연쇄의 표현을 이용하여 공정탐색절차의 특성을 도출하였다. Markov 연쇄의 특성은 전이행렬에 따라 달라지며, 전이행렬은 관리절차와 공정분포에 의해 결정된다. 이 논문에서 도출된 Markov 연쇄의 표현은 많은 다른 형태의 관리절차나 공정분포에서도 그에 해당하는 전이행렬을 구하면 쉽게 적용될 수 있다.

• Journal of the Korean Statistical Society
• /
• 제33권4호
• /
• pp.381-399
• /
• 2004

Statistical process control (SPC) and engineering process control (EPC) are based on different strategies for process quality improvement. SPC re-duces process variability by detecting and eliminating special causes of process variation, while EPC reduces process variability by adjusting compensatory variables to keep the quality variable close to target. Recently there has been need for an integrated process control (IPC) procedure which combines the two strategies. This paper considers a scheme that simultaneously applies SPC and EPC techniques to reduce the variation of a process. The process model under consideration is an IMA(1,1) model with a step shift. The EPC part of the scheme adjusts the process, while the SPC part of the scheme detects the occurrence of a special cause. For adjusting the process repeated adjustment is applied according to the predicted deviation from target. For detecting special causes the exponentially weighted moving average control chart is applied to the observed deviations. It was assumed that the adjustment under the presence of a special cause may increase the process variability or change the system gain. Reasonable choices of parameters for the IPC procedure are considered in the context of the mean squared deviation as well as the average run length.

• 한국환경과학회지
• /
• 제22권7호
• /
• pp.905-913
• /
• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• 대한정형도수물리치료학회지
• /
• 제16권1호
• /
• pp.57-63
• /
• 2010

The palpation of spinous process and transverse process of vertebra are important part of the assesment and treatment from Orthopedic manual therapy. But the palpation area is descriptive differently each of literatures. So we generally got these outcomes. : There are C2, C3, C4 and C6 process as a bony landmarks and these are important part of establish the precise location of pain appears from cervical spine. Even though C7 process regard a prominent part, it is hard to distinguish C6 and process of T1. Thru that differentiation, grab the patient's forehead and try them cervical and hyper-extension check any movement of process or put on the fingers on C7 preocess and check the movement. The palpation of thoracic spine process is the land mark which determines general level orientation in the spine easily, there are T2, T7 spinous process. However, It is depends on how do you test the patient's arm when you palpate it and it can effect on spinous process. The transverse process of C1 is the only spot for palpation in cervical spine, and T1-3, T12 transverse process can palpate it when it stands on the process. The end of T4-6, T11 is placed on middle on vertebra of transverse process and transverse process. T7-9, T10 transverse process is place on same position as spinous process which is upper part of the spine.

• Journal of the Korean Statistical Society
• /
• 제29권3호
• /
• pp.269-284
• /
• 2000

We show asymptotic normality of the sample mean and sample autocovariances function generated from first-order integer valued autoregressive process(INAR(1)) with a negative binomial or a Poisson marginal. It is shown that a Poisson INAR(1) process is a special case of a negative binomial INAR(1) process.

• 상하수도학회지
• /
• 제31권1호
• /
• pp.39-50
• /
• 2017

In the coagulation/sedimentation (C/S) process of the water treatment process, the inflow of massive algal bloom causes many problems including fouling of filter media. This study was conducted to find out the way to remove the algae's harmful effects by addition of pre-treatment prior to C/S process. Many Jar-tests were conducted such as (1) ACF (Algae Coagulation Flotation) process using natural algae coagulant (Water $Health^{(R)}$), (2) ACF + C/S process and (3) C/S process with a variety of conditions using cultured algae. The average values of turbidity were (1) 0.42 NTU for ACF process, (2) 0.13 NTU for ACF + C/S process and (3) 0.25 NTU for C/S process. It was shown that the treatment efficiency of ACF process could get low turbidity results, and ACF + C/S process could achieve more efficient results than those of C/S process. Any negative effects of ACF process to the efficiency of C/S process were not observed in ACF + C/S process. In order to reduce the unfavorable effects of algae, it was found out that the introduction of ACF process in the forms of (1) ACF or (2) ACF + C/S could be one of the effective and alternative solutions.