• IEMEK Journal of Embedded Systems and Applications
• /
• v.19 no.3
• /
• pp.151-158
• /
• 2024

Although on-device artificial intelligence (AI) has gained attention to diagnosing machine faults in real time, most previous studies did not consider the model retraining and redeployment processes that must be performed in real-world industrial environments. Our study addresses this challenge by proposing an on-device AI-based real-time machine fault diagnosis system that utilizes continual learning. Our proposed system includes a lightweight convolutional neural network (CNN) model, a continual learning algorithm, and a real-time monitoring service. First, we developed a lightweight 1D CNN model to reduce the cost of model deployment and enable real-time inference on the target edge device with limited computing resources. We then compared the performance of five continual learning algorithms with three public bearing fault datasets and selected the most effective algorithm for our system. Finally, we implemented a real-time monitoring service using an open-source data visualization framework. In the performance comparison results between continual learning algorithms, we found that the replay-based algorithms outperformed the regularization-based algorithms, and the experience replay (ER) algorithm had the best diagnostic accuracy. We further tuned the number and length of data samples used for a memory buffer of the ER algorithm to maximize its performance. We confirmed that the performance of the ER algorithm becomes higher when a longer data length is used. Consequently, the proposed system showed an accuracy of 98.7%, while only 16.5% of the previous data was stored in memory buffer. Our lightweight CNN model was also able to diagnose a fault type of one data sample within 3.76 ms on the Raspberry Pi 4B device.

• Information Systems Review
• /
• v.20 no.1
• /
• pp.81-98
• /
• 2018

ERP supports the automation and integration of business processes of enterprises and records voluminous data about the business activities of enterprises. The academe and business enterprises are focusing on process mining, which improves the performance of business processes and strengthens compliance. However, these studies focused on analysis of the business process of large companies, which adopts foreign ERP, such as SAP ERP or Oracle ERP. In comparison with foreign ERP, domestic ERP lags behind in terms of logging and managing of event data. Therefore, the application of process mining to domestic ERP is a challenging task. The present study aims to analyze domestic ERP based on process mining to overcome this challenge. This study discusses the lessons learned from a case study in a Korean cosmetics manufacturing company. Our results are expected to strengthen the competitiveness of Korean small and medium-sized enterprises that adopt domestic ERP and realize the outcomes of the large investment of the Korean government on the ERP implementation of enterprises.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.9
• /
• pp.54-62
• /
• 2015

Although NAND flash-based SSD (Solid-State Drive) provides superior performance in comparison to HDD (Hard Disk Drive), it has a major drawback in write endurance. As a result, the lifetime of SSD is determined by the workload and thus it becomes a big challenge in current technology trend of such as the shifting from SLC (Single Level Cell) to MLC (Multi Level cell) and even TLC (Triple Level Cell). Most previous studies have dealt with wear-leveling or improving SSD lifetime regarding hardware architecture. In this paper, we propose the optimal configuration of host I/O stack focusing on file system, I/O scheduler, and link power management using JEDEC enterprise workloads in terms of WAF (Write Amplification Factor) which represents the efficiency perspective of SSD life time especially for host write processing into flash memory. Experimental analysis shows that the optimum configuration of I/O stack for the perspective of SSD lifetime is MinPower-Dead-XFS which prolongs the lifetime of SSD approximately 2.6 times in comparison with MaxPower-Cfq-Ext4, the best performance combination. Though the performance was reduced by 13%, this contributions demonstrates a considerable aspect of SSD lifetime in relation to I/O stack optimization.

• Cross-Cultural Studies
• /
• v.25
• /
• pp.483-527
• /
• 2011

The main focus of this dissertation is the comparative research of Korean and Chinese adjectives. With the comparison and contrast of the concepts, features and usages of Korean and Chinese adjectives, we have concluded some similarities and differences. The aim is to help Chinese learners who study Korean better understand the features of Korean adjectives and use them more easily. Korean belongs to 阿?泰?族 and expresses meanings with pronunciation; however, Chinese belongs to ?藏?族 and expresses meanings with characters. There are many similarities between those two languages that look completely different, such as pronunciation and grammar at some extent. Even the Chinese words in Korean are quite similar to Chinese. However, the two languages are very different from each other, from the detailed grammatical view. For instance, the auxiliary word in Korean and Chinese is completely different. Then, Korean has a concept: ?尾that does not exist in Chinese at all. Especially, about categories of words, it is very important and difficult to distinguish adjective and verb for the Chinese Korean-learners. One reason of the challenge is that some Korean adjectives are categorized as verbs in Chinese. For example, "like", "dislike", "fear" in Korean are "psychological adjective" however, they are "psychological verb" in Chinese. The differences in categorization always mislead learners in understanding whole articles. At the same time, they cause more problems and difficulties in learning other grammatical items for Chinese Korean-learners. Based on that, the dissertation is helpful for Chinese learners who are studying Korean. Starting from the most basic concepts, the second chapter focuses on analyzing the similarities and differences between Korean and Chinese adjectives. The correct understanding of adjective is the basis of accurate learning of it. With the comparison of concepts and primary comprehension of adjective, the third chapter analyzes in detail about the features of Korean and Chinese adjective from grammar and meaning. Based on those features, we analyze the detailed usages of Korean and Chinese adjective in articles; especially we provide the detailed explanations of adjective changes in different tense and ?尾 changes in using with noun and verb. The fourth chapter emphasizes the similarities and differences of adjective meanings in Korean and Chinese. We have provided the comparative analyses from six different views, which could be helpful for Chinese Korean-learners. Until now, there are few comparative studies of Korean and Chinese adjectives. About this dissertation, some limitations also exist in such an area. However, we hope it could provide some help for Chinese Korean-learners, and more profound research will be developed in the future.

• Parasites, Hosts and Diseases
• /
• v.29 no.3
• /
• pp.279-292
• /
• 1991

The immune response to sheep red blood cell (sRBC) was monitored in the mice infected with Ascaris strum or Trichinella spiralis. The effects of the infection with T. spiralis or the injection with cyclophosphamide (CY) as an immunosuppression agent prior to challenge infection with the embryonated eggs of A. suum were monitored in mice by means of the level of infection with A. strum and cellular and humoral immune response to sRBC. following the oral administration of 1, 000 eggs of A. suum to mice, delayed-type hypersensitivity (DTH) and rosette-forming rate were gradually decreased and reached to the lowest levels at the 5th week and 6th week postinfection, respectively, and then returned to normal at the loth week. The hemagglutinin (HA) and hemolysin (HE) titers were gradually elevated and reached to peak at the 3rd week postinfection, and then returned to normal level. The appearance ratios of the eosinophils and mast cells were in peak at the 4th week and the 2nd week postinfection, respectively. Meanwhile the harvest ratio of A. suum larvae from the liver and lungs was 21.97% at the 1st week postinfection. Following the oral administration of 300 T. spiralis infective larvae, DTH and rosette-forming rate were gradually decreased with the lapse of time and reached the lowest values in the 30th and 21st day of postinfection, and then slightly increased and transiently decreased in the 70th and 80th day of postinfection, respectively. HA and HE titers were the lowest in the 21st and 90th day, whereas the ratios of eosinophils and mast cells were the highest on the 40th and 14th day posti nfecti on, ruts petit i vela. Following the intraperitoneal injection of CY, the body weight, the spleen weight, DTH, rosette-orming ratio, HA and HE titers, the number of WBC and the ratio of the mast cell were predominantly decreased in the 5th day, and then returned to the same value of the 1st day postinjection. The ratio of eosinophils was gradually decreased following to advance of days. At the 1st, 5th and loth days after intraperitoneal injection of CY of 400 mg/kg, a dose with 1, 000 eggs of A. suum was administered orally to mice, and harvest rate of the larvae at the 7th day postadministration was 7.07% in the 1st day, 14.94% in the 5th day, 10.1% in the loth day, 8.02% in control group. The effect of prior infection with infective larvae of T. spiralis upon immunological sequelae of a challenge infection of mice with embryonated eggs of A. suum in 30 or 70 days interval was checked. On the 37th day of prior infection with T. spiralis, that was the 7th day with A. suum postinfection, DTH and rosette-forming rate were drastically decreased, but the ratio of mast cells was highly increased and the ratio of eosinophils, HA and HE titers were fairly increased. On the other hand, the rate of larvae harvest was 9.3% in experimental group in contrast with 22.18% in control group. Meanwhile the effect of immune response to sRBC was similar to that of the former, but DTH and rosettt-forming rate were greatly decreased in the 77th day after prior infection with the 7th day after challenge infection in compariton with control. At that time, Ascaris larvae were harvested 8.3% in experimental group in comparison with 10.5% in control group.

• The Korean Journal of Nuclear Medicine
• /
• v.34 no.3
• /
• pp.252-259
• /
• 2000

Purpose: The purpose of this study was to compare the radiation adaptive response (RAR) in peripheral lymphocytes (PL) of patients induced by Tc-99m MDP and Tc-99m DTPA scintigraphies. Materials and Methods: Lymphocytes from 45 patients (25 males, 20 females, mean age $44{\pm}18$ years) were collected before and after scintigraphies using 740 MBq Tc-99m MDP (n=22) or Tc-99m DTPA (n=23). Lymphocytes from 20 controls (12 males, 8 females, mean age $43{\pm}7$ years) were also collected. They were exposed to challenge dose of 2 Gy ${\gamma}-rays$ using a Cs-137 cell irradiator Number of ring-form (R) and dicentric (D) chromosomes was counted under the light microscope. From them a representative score, Ydr, was calculated as Ydr=(D+R)/cells. Adaptation index (AI) was defined as difference of Ydr between unconditioned and conditioned lymphocytes. Ydr was also measured after an administration of cycloheximide (CHM), a protein synthesis inhibitor, before challenge dose. Results: RAR was induced in both groups of patients. CHM abolished the adaptive response in both groups. AI of Tc-99m MDP group was significantly higher than that of Tc-99m BTPA group. Conclusion: Tc-99m MDP induced RAR was more prominent than those induced by Tc-99m DTPA.

• Korean Journal of Veterinary Research
• /
• v.33 no.4
• /
• pp.657-664
• /
• 1993

To reveal the immunogenicity of ${\gamma}-irradiated$ E tenella and its progeny, a series of experiments on the effects of Cobalt-to ${\gamma}-irradiation$ was performed. The SPF chickens inoculated with diffenrt doses of inoculum were challenged with $1{\times}10^5$ oocysts of virulent E tenella. The levels of 100 Gy ${\gamma}-irradiation$ from $^{60}Co$ and of inoculum with $1{\times}10^4$ oocysts were recognized as proper as immunogen by comparison of survival rates, body weight gains, blood in feces and lesion scores in the chickens. In these trials of challenge with virulent E tenella after inoculation with $1{\times}10^4$ oocysts of the ${\gamma}-irradiated$ E tenella and its progeny, the survival rates of the chickens challenged with the virulent E tenella after immunization with the 1st and the 3rd progeny groups of ${\gamma}-irradiated$ E tenella oocysts were higher(l00%) than that(87.0%) of the challenged control group. The signs of blood in feces and the lesion scores were seen markedly lower with the ourput of the smaller number of oocysts, i.e. OPG 103,900 and 25,800 in the groups of the 1st and the 3rd progeny, respectively, than those(OPG 1,658,900) of the challenged control group. The body weight gains of the 1st and the 3rd progeny groups, the 1st week and the 2nd week after challenge, were higher (2.6g and 155.4g, 11.6g and 168.9g respectively) than those(-85.8g and 63.6g, respectively) of the challenged control group, and the feed conversion ratios(FCR 3.28 and 2.96) of the 1st and the 3rd progeny groups were lower than that(FCR 5.60) of the groups challenged control group. The anticoccidial indices(70.5 and 93.9) of the groups challenged with the virulent oocysts of E tenella after immunization with the 1st and the 3rd progeny of the ${\gamma}-irradiated$ E tenella were significantly higher than that (ACI -81.9) of the challenged control group. It was thought that the immunogenicity of ${\gamma}-irradiated$ E tenella would be increase according to increase the number of generation passaged in chicken. That might be because of increasing the pathogenicity of ${\gamma}-irradiated$ E tenella according to increase the number of generation passaged in chicken.

• School Mathematics
• /
• v.19 no.1
• /
• pp.19-41
• /
• 2017

The purpose of this article was to a) identify how preservice teachers conceive feedbacks and subsequent classroom discourses, and b) compare them with those in reform-oriented mathematics classroom video for mathematics teachers' professional development about classroom discourse. This article analyzes feedback patterns and subsequent classroom discourses in preservice teachers' imaginary classroom scripts (lesson plays) and compares them with those in the reform-oriented classroom video dealing with the same teaching situation. Most of the preservice teachers' feedbacks focused the evaluation of students' responses and transmission of meaning (univocal function), whereas the teacher's feedback in the reform-oriented classroom allowed the whole class to validate or challenge the answers, thereby facilitating students' generation of meaning (dialogic function). The comparison analysis between the univocal discourse in a preservice teacher's lesson play and the dialogical discourse in the reform-oriented classroom video shows that teacher feedback serves as an important indicator for the main function of classroom discourse and the levels of students' cognitive participation, and also as a variable that determines and changes them. This case study suggests that to improve the quality of classroom discourse, preservice and in-service teachers need experience of perceiving the variety of feedback patterns available in specific teaching contexts and exploring ways to balance the univocal and dialogical functioning in their feedback move during the teacher training courses.

• Journal of Chest Surgery
• /
• v.34 no.11
• /
• pp.843-847
• /
• 2001

Background: Replacement of the esophagus remains a challenge for surgeons involved in esophageal disease. From 1996 to 1999, a total of 27 patients with esophageal cancer underwent free jejunal transfer(12cases) or esophagogastrostomy(15cases). To determine the results such as leakage of anastomosis site, stenosis, reflux esophagitis and operation time, respiratory complications, etc. we reviewed the 4 years experiences. Material and method: Palliative bypass surgery or esophageal prosthesis and cancers of the pharyngoesophageal or esophagogastric junction were excluded in this study. Resection was usually peformed through right thoracotomy and anastomosis was made with EEA staplers in esophagogas-trstomy. In cases of jejunal free transfer, 6cases of proximal esophagojejunostomy were stapled anastomosed and remaining 6 cases and all distal site were hand-sewn anastomosed. All reconstruction was done through posteromediastinal route. Result: There were two mortalities from thoracic esophagogastrostomy and one from jeunal free transfer. Major and minor complications(anastomosis site leakage: 3 cases, graft failure: 2cases etc) occurred in 27 cases. In 15 thoracic esophagogastrostomy cases, 11 patients had mild to moderate reflux esophagitis and 5 patients incurred stricture of the anastomosis. Operation time was about 550$\pm$280 minutes in jejunal free transfer, and about 300$\pm$ 160 minutes in esophagogastromy patients. Conclusion: Post operative reflux esophagitis and dysphagia were more frequent in Ivor-Lewis operation group than jejunal free transfer group; however, respiratory complications and operation time were significantly longer in jejunal (roe transfer group(p<0.05). To minimize the incidence of postoperative reflux esophagitis and dysphagia, patient evaluation focused on jejunal free transfer surgery is better than esophagogastrostomy followed by adequate post operative care.

• Journal of Korean Neurosurgical Society
• /
• v.59 no.6
• /
• pp.564-569
• /
• 2016

Objective : This study used the intradural procedural time to assess the overall technical difficulty involved in surgically clipping an unruptured middle cerebral artery (MCA) aneurysm via a pterional or superciliary approach. The clinical and radiological variables affecting the intradural procedural time were investigated, and the intradural procedural time compared between a superciliary keyhole approach and a pterional approach. Methods : During a 5.5-year period, patients with a single MCA aneurysm were enrolled in this retrospective study. The selection criteria for a superciliary keyhole approach included : 1) maximum diameter of the unruptured MCA aneurysm <15 mm, 2) neck diameter of the MCA aneurysm <10 mm, and 3) aneurysm location involving the sphenoidal or horizontal segment of MCA (M1) segment and MCA bifurcation, excluding aneurysms distal to the MCA genu. Meanwhile, the control comparison group included patients with the same selection criteria as for a superciliary approach, yet who preferred a pterional approach to avoid a postoperative facial wound or due to preoperative skin trouble in the supraorbital area. To determine the variables affecting the intradural procedural time, a multiple regression analysis was performed using such data as the patient age and gender, maximum aneurysm diameter, aneurysm neck diameter, and length of the pre-aneurysm M1 segment. In addition, the intradural procedural times were compared between the superciliary and pterional patient groups, along with the other variables. Results : A total of 160 patients underwent a superciliary (n=124) or pterional (n=36) approach for an unruptured MCA aneurysm. In the multiple regression analysis, an increase in the diameter of the aneurysm neck (p<0.001) was identified as a statistically significant factor increasing the intradural procedural time. A Pearson correlation analysis also showed a positive correlation (r=0.340) between the neck diameter and the intradural procedural time. When comparing the superciliary and pterional groups, no statistically significant between-group difference was found in terms of the intradural procedural time reflecting the technical difficulty (mean${\pm}$standard deviation : $29.8{\pm}13.0min$ versus $27.7{\pm}9.6min$). Conclusion : A superciliary keyhole approach can be a useful alternative to a pterional approach for an unruptured MCA aneurysm with a maximum diameter <15 mm and neck diameter <10 mm, representing no more of a technical challenge. For both surgical approaches, the technical difficulty increases along with the neck diameter of the MCA aneurysm.