• Journal of Digital Contents Society
• /
• v.14 no.3
• /
• pp.349-356
• /
• 2013

Products of Wi-Fi devices in recent years offer higher throughput and have longer signal coverage which also bring unnecessary signal interference to neighboring wireless networks, and result in decrease of network throughput. Signal interference is an inevitable problem because of the broadcast nature of wireless transmissions. However it could be optimized by reducing signal coverage of wireless devices. On the other hand, smaller signal coverage also means lower transmission power and lower data throughput. Therefore, in this paper, we analyze the relationship among signal strength, coverage and interference of Wi-Fi networks, and as a tradeoff between transmission power and data throughput, we propose a range-aware Wi-Fi network scheme which controls transmission power according to positions and RSSI(Received Signal Strength Indication) of Wi-Fi devices and analyze the efficiency of the proposed scheme by simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.12
• /
• pp.39-44
• /
• 2010

In LTE-Advanced systems, every sector uses the entire range of the frequency resource, and when the UEs are located at a cell edge, user throughputs degrade due to the interferences from the adjacent cells. In this paper, we propose a combined scheme for inter-cell interference avoidance and power control. In the proposed algorithm, the sectors consist of the right edge, the left edge and the center for resource allocation and we control the transmission power to improve the user throughputs at the edge of each cell. Using a system level simulation, we analyze low 5th percentile and average user throughputs of the UEs who are located the cell, center and edge when the inter-cell interference avoidance and the power control are combined.

• The Journal of Bigdata
• /
• v.3 no.1
• /
• pp.95-103
• /
• 2018

In recent years, many people in the manufacturing field have been making efforts to increase efficiency while analyzing manufacturing data generated in the process according to the development of ICT technology. In this study, we propose a data mining based manufacturing process using decision tree algorithm (CHAID) as part of a smart factory. We used 432 sensor data from actual manufacturing plant collected for about 5 months to find out the variables that show a significant difference between the stable process period with low defect rate and the unstable process period with high defect rate. We set the range of the stable value of the variable to determine whether the selected final variable actually has an effect on the defect rate improvement. In addition, we measured the effect of the defect rate improvement by adjusting the process set-point so that the sensor did not deviate from the stable value range in the 14 day process. Through this, we expect to be able to provide empirical guidelines to improve the defect rate by utilizing and analyzing the process sensor data generated in the manufacturing industry.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.625-636
• /
• 2017

Dyslipidemia, hypertension, and diabetes are well-established risk factors for cardio-cerebrovascular disease (CVD). Although the prevalence of dyslipidemia among Korean adults is very high, its management is known to be poor. The aim of this study was to assess the prevalence, awareness, treatment, and control rates of dyslipidemia among adults aged 30 years and older in Gangwon-do, Korea. Analysis included 58,121 adults (29,123 males and 28,998 females) participating in the 2013-2014 Korea National Health Screening Program (KNHSP). Dyslipidemia was defined according to the treatment criteria rather than the diagnostic criteria in Korea. Therefore, high-low-density lipoprotein cholesterol (LDL)-cholesterolemia was deemed present in individuals with LDL-cholesterol levels that exceeded the appropriate risk-based threshold. The age-standardized prevalence was highest in dyslipidemia (32.5%), followed by hypertension (25.1%), and diabetes (9.4%). The awareness rate was 76.7% for hypertension and 74.7% for diabetes, but only 10.6% for dyslipidemia. The lowest patient treatment was found for dyslipidemia (9.4%). The control rate among those undergoing treatment was highest for hypertension (75.8), followed by dyslipidemia (63.3%), and diabetes (43.9%). The higher CVD-risk categories showed lower control rates of hyper-LDL-cholesterolemia. The prevalence of dyslipidemia was higher than hypertension and diabetes, but awareness and treatment rates were lower. Our findings indicate there is a wide gap between the prevalence of dyslipidemia and subsequent treatment, which suggests that effective strategies are required to improve dyslipidemia management. It would be worthwhile to strengthen the follow-up management of patients with dyslipidemia in the KNHSP, especially for the high risk group of CVD.

• Journal of Digital Convergence
• /
• v.10 no.10
• /
• pp.165-176
• /
• 2012

Despite the gradual growth of mobile markets according to an increased mobile distribution rate, empirical studies on the mobile shopping application markets are not sufficient. From the viewpoint of a large number of purchase of brand product in department store by customers and a high growth rate of mobile shopping by means of mobile shopping, we classified a principle variable, the interactivity, into three levels and verified the effects of the interactivity on the flow, effects of the flow on the purchase intention and the control effect of purchase level. In conclusion, among the three levels of the interactivity the customer-customer interactivity and the content-customer interactivity have positive effects on the flow, but company-customer has not. On the other hand, the customer-customer interactivity and the content-customer interactivity have a positive effect on the flow. Furthermore, the flow affects the purchase intention positively. After the verification of the direct effect of interactivity on the purchase intention, the content-customer interactivity only has a positive effect on the purchase intention. Lastly, the purchase level has a control effect when the customer-customer interactivity has a positive effect on the flow.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.9A
• /
• pp.1285-1294
• /
• 1999

In this paper we consider the performance of TCP video traffic over ABR with Long-Range Dependent VBR traffic. As compressed coded video traffics are increasing rapidly over Internet, lots of studies are being done for transmitting those traffics efficiently using limited network resources. We consider here the transmitting video service over ABR service in ATM networks, especially satellite networks. CBR or VBR services are suggested in transmitting the video traffic in ATM Forum TM 4.0. But ABR service connection, which is considered as appropriate service for data traffic, can be established with a small amount of bandwidth, MCR (Minimum cell rate). Furthermore ABR service can control the source's transmitting rate using feedback mechanism. Using this feature ABR service can be used in some applications which can control their quality of services corresponding to network loads. Compressed video sources with MPEG-2 are used for Long-Range Dependent VBR traffic here. We model the compressed video source to resemble the MPEG-2 transport streams. These compressed video traffic streams are consisted of three different frames, I-frame, P-frame, and B-frame. So when a network are overloaded, we can control the quality of service using this traffic features. TCP Traffics over ABR need large buffers in ATM switch to satisfy their QoS with background VBR traffics, which have high deviations in bandwidth. Furthermore satellite ATM networks with large feedback delay need large buffers corresponding RTT delay. The performance comparisons among EFCI and ER switch (ERICA+) switches in the network circumstances described above were shown in this paper. We also considered the case with ON-OFF VBR traffics.

• Journal of Aquaculture
• /
• v.4 no.2
• /
• pp.85-95
• /
• 1991

Spawning inducement of flounder, Paralichthys olivaceus, was attemped by the control of water temperature and photoperiod from June 1, 1989 through January 5, 1990 (189 days) Water temperature was gradually decreased from $21.7^{\circ}C$ to $10.6^{\circ}C$ which was the minim biological temperature for spawning of flounder. Water temperature was increased asain to $15^{\circ}C$ gradually, and then maintained at this level through the end of spawning. Photoperiod was also changed gradually from 10L/14D in June 1, 1989 to 14L/10D in July 25, 1989. Spawning of the fish occurred from October 4, 1989 through January 5, 1990 (93 days). The average number of eggs spawned during the spawning season per female were 2.67 billion. The first spawning occurred on the 60th day after the time of minimun water temperature $10.6^{\circ}C$. The water temperature and photoperiod at the first spawning were $13^{\circ}C$ and 14L/10D respectively It took 71 days to spawn since the photoperiod had changed from 10L/14D to 14L/10D. Spawning period can be devided into three terms. The first term was continued for 30 days from the beginning of the spawning. The second term for 41 days was the major spawning period followed by the third term, the final period of the spawning, for 22 days. The percentage of average fertilization rate of the eggs in the first, second and third spawning terms were $37.4{\%},\;54.1\%\;and\;19.6\%$, respectively. Feeding rate was increased in the maturing period but, decreased in the spawing period. During the final spawning period, the abrubt decreasing of the feeding occurred again.

• Journal of Intelligence and Information Systems
• /
• v.27 no.3
• /
• pp.113-137
• /
• 2021

According to the clear potential of mobile banking growth, many studies related to this are being conducted, but in Korea, it is concentrated on the analysis of technical factors or consumers' intentions, behaviors, and satisfaction. In addition, even though it has a strong customer base of 20s, there are few studies that have been conducted specifically for this customer group. In order for mobile banking to take a leap forward, a strategy to secure various perspectives is needed not only through research on itself but also through research on external factors affecting mobile banking. Therefore, this study analyzes impulsiveness, credit card use, and SNS addiction among various external factors that can significantly affect mobile banking in their 20s. This study examines whether the relationship between impulsiveness and mobile banking usage depends on whether or not a credit card is used, and checks whether a customer's impulsiveness is possible by examining whether a credit card is used. Based on this, it is possible to establish new standards for classification of marketing target groups of mobile banking. After finding out the static or unsuitable relationship between whether to use a credit card and impulsiveness, we want to indirectly predict the customer's impulsiveness through whether to use a credit card or not to use a credit card. It also verifies the mediating effect of SNS addiction in the relationship between impulsiveness and mobile banking usage. For this analysis, the collected data were conducted according to research problems using the SPSS Statistics 25 program. The findings are as follows. First, positive urgency has been shown to have a significant static effect on mobile banking usage. Second, whether to use credit cards has shown moderating effects in the relationship between fraudulent urgency and mobile banking usage. Third, it has been shown that all subfactors of impulsiveness have significant static relationships with subfactors of SNS addiction. Fourth, it has been confirmed that the relationship between positive urgency, SNS addiction, and mobile banking usage has total effect and direct effect. The first result means that mobile banking usage may be high if positive urgency is measured relatively high, even if the multi-dimensional impulsiveness scale is low. The second result indicates that mobile banking usage rates were not affected by the independent variable, negative urgency, but were found to have a significant static relationship with negative urgency when using credit cards. The third result means that SNS is likely to become addictive if lack of premeditation or lack of perseverance is high because it provides instant enjoyment and satisfaction as a mobile-based service. This also means that SNS can be used as an avoidance space for those with negative urgency, and as an emotional expression space for those with high positive urgency.

• Journal of Bio-Environment Control
• /
• v.21 no.3
• /
• pp.252-260
• /
• 2012

This study was carried out to compare the storability in MA storage and quality of paprika fruits among 9 cultivars grown in 2011 and 12 cultivars in 2012. 'Mosanto 7044' was the most proper cultivar in red-type paprika has grown in 2011 for MA storage, because it showed relatively higher fruit weight, firmness, soluble solid content, and the lowest ethylene production rate, as well as the second longest shelf life. 'Stayer' was suitable cultivar in yellow-type paprika cultivated in 2011, because it showed higher firmness, soluble solid content and lower ethylene production rate than other cultivars. 'Nagano' was the most proper cultivar in red-type paprika has grown in 2012 for MA storage. Because it showed relatively higher fruit weight, firmness, flesh thickness and the lowest ethylene production rate and decay ratio, although the shelf life of 'Nagano' was the third longest (28 days). 'Freestar' was the excellent cultivar in yellow-type paprika cultivated in 2012, because it showed higher firmness, vitamin C content and lower respiration rate than other cultivars and the longest shelf life of 26 days. The shelf life had a high correlationship with ethylene production rate (r = -0.5504), and soluble solid (r = 0.6112), as comparing with the shelf life and the fruit characteristics of 21 cultivars paprika has grown in 2011 and 2012.

• Journal of Bio-Environment Control
• /
• v.24 no.3
• /
• pp.202-209
• /
• 2015

This study compared and analyzed the measurements of pullout load according to the depth of reclamation in the foundation, compaction ratio of soil, spiral diameter, and soil textures in an experiment with a model and reached the following conclusions: The comparison results of extreme pullout load between farm and reclaimed soil show that farmland soil recorded a score that was 1.2~3 times higher than that of reclaimed soil. The investigator measured pullout load in farmland and reclaimed soil and observed a tendency of rising extreme pullout load according to the increasing depth of reclamation and compaction ratio with a similar load-displacement curve between the two types of soil. Extreme pullout load made a greater increase by the rising size of diameter than the increasing depth of reclamation, also making a considerably bigger increase according to the rising compaction ratio than the other conditions. Therefore, the spirals bar is expected to be available in soft soil foundation, as well as farmland as increasing buried deep of foundations, compaction rate, diameter of the spiral, ect.