• Design & Manufacturing
• /
• v.12 no.3
• /
• pp.55-59
• /
• 2018

In a multi-cavity mold having a runner layout of a fish bone structure, problems of unbalanced filling between cavities occur constantly. Unbalanced charging lowers the dimensional accuracy of a molded article and causes deformation after molding. To solve this problem, the gate size connected to each cavity is adjusted using the BGV (Balanced Gate Value) equation. In this paper, in order to solve the filling imbalance problem of the runner layout mold of fish bone structure through injection molding analysis study, we compared the charging imbalance phenomenon before and after improvement after adjusting the gate size by applying BGV equation. From the results of the molding analysis, the shrinkage ratio before and after the improvement of the molded article was improved by only about 0.08%. Based on these results, it was confirmed that the charging imbalance problem was not significantly improved even when the BGV equation was applied.

• International Journal of Computer Science & Network Security
• /
• v.22 no.10
• /
• pp.11-16
• /
• 2022

Applying predictive analytics to predict software defects has improved the overall quality and decreased maintenance costs. Many supervised and unsupervised learning algorithms have been used for defect prediction on publicly available datasets. Most of these datasets suffer from an imbalance in the output classes. We study the impact of class imbalance in the defect datasets on the efficiency of the defect prediction model and propose a CPP method for handling imbalances in the dataset. The performance of the methods is evaluated using measures like Matthew's Correlation Coefficient (MCC), Recall, and Accuracy measures. The proposed sampling technique shows significant improvement in the efficiency of the classifier in predicting defects.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.10 no.2
• /
• pp.155-162
• /
• 2016

The purpose of this study was to determine the walking imbalance using the EMG(electromyogram). To confirm the effectiveness of the proposed encoder and acceleration, EMG sensor based gait imbalance determination system. This experiment was carried out to evaluation with a healthy adult male to 10 people. The Encoder device is attached to the hip and knee joint in order to measure the gait signal. The Accelerometer sensors are attached on the ankle. The EMG sensors are attached on the vastus lateralis and anterior tibialis. SI(Symmetry Index) was used as an index for determining the gait imbalance. To confirm if the judgment has been made correctly, the heel, regarded as the cause of unbalanced ambulation, was adjusted from 0 cm to 6 cm with intervals of 1.5 cm. In the cases of the encoder and the EMG, the difference of 0 cm and 1.5 cm is determined into normal walk but the other difference is distinguished into gait imbalance. In the case of the accelerometer, the difference of 0 cm, 1.5 cm and 3 cm is determined into normal walk but the other difference is distinguished into gait imbalance.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.2
• /
• pp.18-26
• /
• 2015

In this paper, we studied the method for analyzing and estimating the parameters that induce I/Q imbalance in the repeater using direct conversion RF. In repeater, amplitude, phase, and filter mismatch are generated in the receiving-end which converts RF signal to baseband signal. And amplitude and phase mismatch are generated in the transmitting-end which converts baseband signal to RF signal. Accordingly, we modeled the parameters that cause I/Q imbalance in the structure of the repeater in order, and proposed a feedback test structure from the transmitting-end to the receiving-end for estimating the corresponding parameters. By comparing the test transmitting signal and received signal, it is possible to estimate the I/Q imbalance parameters which occurred from mixed components of real and imaginary part. And it was confirmed that I/Q imbalance phenomenon has been properly compensated with estimated parameters at the direct conversion RF repeater.

• Journal of Intelligence and Information Systems
• /
• v.14 no.3
• /
• pp.133-154
• /
• 2008

The data imbalance problem which can be uncounted in data mining classification problems typically means that there are more or less instances in a class than those in other classes. In order to solve the data imbalance problem, there has been proposed a number of techniques based on re-sampling with replacement, adjusting decision thresholds, and adjusting the cost of the different classes. In this paper, we study the feasibility of the combination usage of the techniques previously proposed to deal with the data imbalance problem, and suggest a combination method using genetic algorithm to find the optimal combination ratio of the techniques. To improve the prediction accuracy of a minority class, we determine the combination ratio based on the F-value of the minority class as the fitness function of genetic algorithm. To compare the performance with those of single techniques and the matrix-style combination of random percentage, we performed experiments using four public datasets which has been generally used to compare the performance of methods for the data imbalance problem. From the results of experiments, we can find the usefulness of the proposed method.

• International Area Studies Review
• /
• v.14 no.1
• /
• pp.121-138
• /
• 2010

This paper investigates the effectiveness of the Bretton Woods II hypothesis, by analysing the relationship between the exchange rates and the U.S. current account against 9 Asian countries for the period of 1999-2008. According to the estimation results, It is found that the Asian currencies' real depreciation significantly have worsened the U.S. current account against the Asian countries. Also, the U.S. current account was significantly affected by GDP and investment of the U.S. and the Asian countries. Thus, It is hard to say that the main driver of the global imbalance is the exchange rates devaluation policies of Asian countries as the Bretton Woods II hypothesis argues. The global imbalance is more likely to be complementally affected by savings glut in the Asian region and the deficiency of net saving in the U.S. Therefore, the global imbalance is expected to adjust when economic conditions besides exchange rates change.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.2
• /
• pp.65-76
• /
• 2022

Recently, not only traditional statistical techniques but also machine learning algorithms have been used to make more accurate bankruptcy predictions. But the insolvency rate of companies dealing with financial institutions is very low, resulting in a data imbalance problem. In particular, since data imbalance negatively affects the performance of artificial intelligence models, it is necessary to first perform the data imbalance process. In additional, as artificial intelligence algorithms are advanced for precise decision-making, regulatory pressure related to securing transparency of Artificial Intelligence models is gradually increasing, such as mandating the installation of explanation functions for Artificial Intelligence models. Therefore, this study aims to present guidelines for eXplainable Artificial Intelligence-based corporate bankruptcy prediction methodology applying SMOTE techniques and LIME algorithms to solve a data imbalance problem and model transparency problem in predicting corporate bankruptcy. The implications of this study are as follows. First, it was confirmed that SMOTE can effectively solve the data imbalance issue, a problem that can be easily overlooked in predicting corporate bankruptcy. Second, through the LIME algorithm, the basis for predicting bankruptcy of the machine learning model was visualized, and derive improvement priorities of financial variables that increase the possibility of bankruptcy of companies. Third, the scope of application of the algorithm in future research was expanded by confirming the possibility of using SMOTE and LIME through case application.

• Korean Journal of Occupational Health Nursing
• /
• v.31 no.2
• /
• pp.77-85
• /
• 2022

Purpose: This study aimed to identify the influence of effort-reward imbalance and job satisfaction on turnover intention among hospital nurses. Methods: Data were collected from January 28 to February 10, 2022, from 237 nurses from five hospitals including clinics, general hospitals, and tertiary care hospitals located in B city. The collected data were analyzed using descriptive statistics, t-test, ANOVA, the Scheffe test, Pearson's correlation coefficients, and multiple linear regression analysis, using SPSS/WIN 26.0. Results: The average of the effort-reward ratio, an indicator of effort-reward imbalance, was 1.67±0.66, and 86.5% of the participants had a value of 1 or more. The mean job satisfaction and turnover intention were 3.32±0.48 and 3.69±0.89 on a 5-point scale, respectively. Multiple regression revealed that factors affecting turnover intention among hospital nurses included effort-reward imbalance (β=.30, p<.001) and job satisfaction (β=-.32, p<.001), and these variables explained 29.0% of turnover intention. Conclusion: These findings indicate that effort-reward imbalance and job satisfaction are associated with turnover intention. Therefore, to decrease the turnover intention of hospital nurses, interventions and policies should be prepared to resolve the nurse's effort-reward imbalance and increase job satisfaction at regional or national level hospitals.

• Information Systems Review
• /
• v.18 no.2
• /
• pp.23-38
• /
• 2016

Previous studies on information systems (IS) and finance suggest that information on stock message boards influence the investment decisions of individual investors. However, how information on online stock message boards influences an individual investor's buy or sell decisions is unclear. To address this research question, we investigate the relationship between a number of posts on stock message boards and order imbalance in stock markets. Order imbalance is defined as the difference between the daily sum of buy-side shares traded and the daily sum of sell-side shares traded. Therefore, order imbalance can suggest the direction of trades and the strength of the direction with trading volumes. In this regard, this study examines how the number of posts (information on stock message boards) influences order imbalance (stock trading behavior). We collected about 46,077 messages of 40 companies on the Korea Composite Stock Price Index from Paxnet, the most popular Korean online stock message board. The messages we collected were divided based on in-trading and after-trading hours to examine the relationship between the numbers of posts and trading volumes. We also collected order imbalance data on individual investors. We then integrated the balanced panel data sets and analyzed them through vector regression. We found that the number of posts on online stock message boards is positively related to prior order imbalance. We believe that our findings contribute to knowledge in IS and finance. Furthermore, this study suggests that investors should carefully monitor information on stock message boards to understand stock market sentiments.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.11 no.2
• /
• pp.115-124
• /
• 2017

This study was to develop the balance insole system for detecting and improving the muscle imbalance of left and right side in lower limbs. We were to verify the validation of balance insole system by analyzing the strategy of muscular activities and foot pressure according to sound feedback. We developed the balance insole based FSR sensor modules for estimating the muscle imbalance using detecting foot pressure. The insole system was FPCB have 8-spot FSR sensor with sensitivity range of 64-level. The participants were twenty peoples who have muscle strength differences in left and right legs over 20%. We measured the muscular activity and foot pressure of left and right side of lower limbs in various gait environment for verifying the improvement effect of muscle imbalance according to sound feedback. They performed gait in slope at 0, 5, 10, 15% and velocity at 3, 4, 5km/h. The result showed that the level of muscle imbalance reduced within 30% for sound feedback of balance insole system contrast to high level of muscle imbalance at 169.9~246.8% during normal gait for increasing slope and velocity. This study found the validation of balance insole system with sound feedback stimulus. Also, we thought that it is necessary to research on the sensitivity of foot area, detection of muscle imbalance and processing algorithm of correction threshold spot.