• Journal of Electrical Engineering and Technology
• /
• v.11 no.6
• /
• pp.1846-1856
• /
• 2016

This study proposes a novel feature point initialization method in order to improve the accuracy of feature point positions by fusing a vision sensor and a lidar. The initialization is a process that determines three dimensional positions of feature points through two dimensional image data, which has a direct influence on performance of a 6-DoF bearing-only SLAM. Prior to the initialization, an extrinsic calibration method which estimates rotational and translational relationships between a vision sensor and lidar using multiple calibration tools was employed, then the feature point initialization method based on the estimated extrinsic calibration parameters was presented. In this process, in order to improve performance of the accuracy of the initialized feature points, an iterative automatic scaling parameter tuning technique was presented. The validity of the proposed feature point initialization method was verified in a 6-DoF bearing-only SLAM framework through an indoor and outdoor tests that compare estimation performance with the previous initialization method.

• Journal of the Korean Home Economics Association
• /
• v.43 no.11 s.213
• /
• pp.127-140
• /
• 2005

Sanitary management performance and knowledge of employees in hospital food service was evaluated by survey questionnaire to improve their sanitary management performance, analyse the weak points of sanitary management, and determine more practical and efficient alternatives of sanitation education. For this study, we selected 6 dieticians and 250 employees working in the six general hospitals larger than 400 beds in Gyeonggi and Incheon area. The questionnaire consisted of three parts: general subjects in the nutrition division of hospitals, sanitation education of dieticians, and sanitary management performance and knowledge of employees. The average ratio of HACCP related equipment and facilities of the target hospitals was relatively high at $86.5\%$. The number of sanitation education was 1.99 times/month by regular schedule and 6.47 times/month by occasional schedule. The average dietician's inspection time of cooking was 178.77 minutes/day. The average point of sanitary management performance was 4.62/5.0, showing a relatively high grade. In each region of sanitary management performance, food treatment sanitation was marked with the highest point, at 4.85, fellowed by cleaning and sterilizing sanitation at 4.65, personnel sanitation at 4.61 point and device and utensil sanitation was ranked with the lowest point at 4.53. Sanitary management performance was affected by the number of occasional education which was highest at 6-10times/month. The mean score of sanitary knowledge was 11.17/15.0. The assigned position, type of employment, status, working career and number of occasional education affected the mean score of sanitary knowledge of employees significantly. Sanitary knowledge of employees was highest in the case that occasional education was peformed at 6-10 times/month. There was no correlation between the sanitary management performance and sanitary knowledge of employees. In contrast, there were correlations between sanitary management performance and dietician's inspection time of cooking and number of employees.

• Journal of Energy Engineering
• /
• v.24 no.2
• /
• pp.144-153
• /
• 2015

At low temperature, Wax build-up and settling can affect adversely the cold weather performance of the diesel vehicle. In this study, we test the cold properties of diesel by blending ratio of biodiesel, kerosene and WAFI. Also, we test the cold weather performance for diesel vehicle by fuel cold properties. Cold properties of diesel are improved by adding the WAFI, kerosene and get worse by adding the biodiesel. WAFI is effective to improve a cold filter plugging point(CFPP) and Kerosene is effective to improve a cloud point(CP). CFPP and pour point(PP) are related to cold weather performance of diesel vehicle but CP is unrelated. CFPP indicate a limit temperature of vehicle driving possibility.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.12
• /
• pp.79-90
• /
• 2000

In this paper, a high-performance floating point unit, which is suitable for high-performance superscalar microprocessors and supports IEEE 754 standard, is designed. Floating-point arithmetic unit (AU) supports all denormalized number processing through hardware, while eliminating the additional delay time due to the denormalized number processing by proposing the proposed gradual underflow prediction (GUP) scheme. Contrary to the existing fixed-radix implementations, floating-point divide/square root unit adopts a new architecture which determines variable length quotient bits per cycle. The new architecture is superior to the SRT implementations in terms of performance and design complexity. Moreover, sophisticated exception prediction scheme enables precise exception to be implemented with ease on various superscalar microprocessors, and removes the stall cycles in division. Designed floating-point AU and divide/square root unit are integrated with and instruction decoder, register file, memory model and multiplier to form a floating-point unit, and its function and performance is verified.

• Journal of KIBIM
• /
• v.10 no.4
• /
• pp.32-39
• /
• 2020

In recent years, the construction industry is getting bigger and more complex, so it is becoming difficult to acquire point cloud data for construction equipments and workers. Point cloud data is measured using a drone and MMS(Mobile Mapping System), and the collected point cloud data is used to create a 3D digital map. In particular, the construction site is located at outdoors and there are many irregular terrains, making it difficult to collect point cloud data. For these reasons, adopting a noise reduction algorithm suitable for the characteristics of the construction industry can affect the improvement of the analysis accuracy of digital maps. This is related to various environments and variables of the construction site. Therefore, this study reviewed and analyzed the existing research and techniques on the noise reduction algorithm. And based on the results of literature review, performance evaluation of major noise reduction algorithms was conducted for digital maps of construction sites. As a result of the performance evaluation in this study, the voxel grid algorithm showed relatively less execution time than the statistical outlier removal algorithm. In addition, analysis results in slope, space, and earth walls of the construction site digital map showed that the voxel grid algorithm was relatively superior to the statistical outlier removal algorithm and that the noise removal performance of voxel grid algorithm was superior and the object preservation ability was also superior. In the future, based on the results reviewed through the performance evaluation of the noise reduction algorithm of this study, we will develop a noise reduction algorithm for 3D point cloud data that reflects the characteristics of the construction site.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.6 no.2
• /
• pp.133-139
• /
• 1982

One of factors that affect combustion in the cylinder of the engine is to keep a greater energy in the ignition system to minimize pollutant emissions and to increase its performance of the low temperature. This paper reviews theoretically the state and input variables of the ignition system from the state transition equation. Effects on characteristics of the system such as primary current, secondary available voltage and spark duration by reducing the pre-resistance from 3.5 to 0 ohm in 12V system is experimentally investigated when the ignition coil has a primary resistance of 1.5 ohms ad the dwell angle of the breaker point is 43.2 degrees (0.75 radian). Advantages and limitations for using the low resistance of the primary circuit are also presented to optimize the performance of the ignition system with the breaker point.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.15 no.1
• /
• pp.3-14
• /
• 1991

This thesis investigates influential attributes in clothing purchase through the examination of questionnaire concerning consumer satisfaction at the point of purchase, and clarifies the relationship between consumer satisfaction at the point of purchase and that in wearing. The results are as follows; 1. At interest stage, color, beauty, becomingness and suitability to occasion are influential (in this order): at trial stage, becomingess, color, others' reaction and fit: at adaption stage, color, becomingness, beauty, fit. 2. According to canonical analysis, consumer satisfaction at the point of purchase and that in wearing are closely related. (RCI = .97) It suggests that satisfaction in wearing depends largely on satisfaction at the point of purchase. 3. General satisfaction in wearing is closely related with such factors as predictive expecta-tion, satisfaction at the point of purchase, predictive disconfirmation, normative disconfirrna-tion, and product performance. According to repression results, those factors can explain $79\%$ of satisfaction ill wearing (R = .79). Above all, product performance and normative disconfirmation are highly influential.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.6 no.4
• /
• pp.138-146
• /
• 1997

The optimal drill helix angle, point angle, and cutting conditions are recommended in the study so as to maximize the drilling performance by investigating the experimental reaults concerning with the state of chip formation, roundness of machined holes, and geometry of projected burr at hole exit, which are examined under the conditions of various helix angles, drill point angles of twist drill, cutting speeds, and feeds in operional parameters. In the easiness of chip escape, the helical type of chip is producted when a helix angle is 30$^{\circ}$, drill point angle 118$^{\circ}$, 140$^{\circ}$and feed is st between 0.1 and 0.15mm/rev. Roundness of machined hole is improved when the helix angle is 37$^{\circ}$, drill point angle is 118$^{\circ}$, and feed is 0.15mm/rev. The height of projected burr at the button of machined hole increases when the drill point angle and helix angle becomes large.

• International Journal of Highway Engineering
• /
• v.14 no.5
• /
• pp.85-91
• /
• 2012

PURPOSES: In this study, various laboratory tests were performed to investigate the suitability of wasted vinyl as a modifier of asphalt binder. METHODS: Based on the ASTM specification, variations in material properties of asphalt binder such as penetration, flash point, softening point, ductility, penetration index (PI), and performance grade (PG) with vinyl content were tested and analyzed. RESULTS: Lavoratory tests revealed that penetration and ductility of the asphalt binder increased with the vinyl content. The flash point, softening point, and PI decreased, and PG changed from 64-22 to 70-22 with increase of the vinyl content. CONCLUSIONS: Wasted vinyl modified the material properties of the asphalt binder. However, the asphalt binder with vinyl content over 6.0% was unsuitable as a pavement material.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.7
• /
• pp.137-143
• /
• 1997

In this study, handling simulation of a passenger car is carried out to see the effects of suspension compliance, roll stabilizef bar and chassis flexibility. The front suspension of the car is a MacPherson strut type and the rear suspension is a multi-link type. The following five DADS models are constructed and compared to verify the effects of suspension compliance and chassis flexibility during lane change. (1) Vdhicle model without hard point compliance and stabilizer, (2) Vehicle model with hard point compoiance, (3) Vehicle model with hard point compliance and stabilizer, (4) Vehicle model with hard point compoiance, stabilizer, and one vibration mode of the chaxxis. (5) Vehicle model with hard point compliance, stabilizer, and three vibration modes of the chassis. The result shows that hard point compliance and stabilizer are significant in roll angle, and the flexibility of the chassis affects the yaw angle and yaw rate.