• Nuclear Engineering and Technology
• /
• v.23 no.1
• /
• pp.1-11
• /
• 1991

The objective of this study is to investigate the effect of weld line on the mechanical strengths and the process of weld line elimination in the Zircaloy-4 resistance upset welding for the fabrication of heavy water reactor fuel rods. The weld current and the amount of upset increased linearly with the main heat, in which two relations between them were derived. It was found that the threshold to obtain sound weld was 50% of main heat in terms of weld upset size, mechanical strengths and weld line elimination. The weld microstructure of resistance upset welds of Zircaloy-4 comprsied basketweave, Widmanstatten and martensite respectively by changing the main heats. Dimples on uniaxially fractured surface at weld line in the Zr-4 welds were larger and deeper compared with those on biaxially fractured surface. It was also found that the process of the weld line elimination in the resistance upset weld of Zircaloy-4 could be divided into three stages in terms of the presence of many pores, their shrinkage and elimination, and the shrinkage of the original weld interface with increasing weld currents.

• The Journal of the Acoustical Society of Korea
• /
• v.40 no.5
• /
• pp.523-529
• /
• 2021

In this paper, we designed and developed an Emotional Speech Synthesis Markup Language (SSML) processor. Multi-speaker emotional speech synthesis technology that can express multiple voice colors and emotional expressions have been developed, and we designed Emotional SSML by extending SSML for multiple voice colors and emotional expressions. The Emotional SSML processor has a graphic user interface and consists of following four components. First, a multi-speaker emotional text editor that can easily mark specific voice colors and emotions on desired positions. Second, an Emotional SSML document generator that creates an Emotional SSML document automatically from the result of the multi-speaker emotional text editor. Third, an Emotional SSML parser that parses the Emotional SSML document. Last, a sequencer to control a multi-speaker and emotional Text-to-Speech (TTS) engine based on the result of the Emotional SSML parser. Based on SSML which is a programming language and platform independent open standard, the Emotional SSML processor can easily integrate with various speech synthesis engines and facilitates the development of multi-speaker emotional text-to-speech applications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.115-123
• /
• 2021

In recent years, the automobile industry has been facing a major change with the introduction of new technologies represented by autonomous driving, electrification, and digitalization. Major domestic and overseas automakers are trying to use a systematic approach to customer satisfaction through user interfaces to provide customers with a special experience and value beyond just making products with high performance. This study proposes the Kano model as a systematic and qualitative research method for satisfaction. As a case study, 17 functions of a product were sorted (3 operation functions, 7 safety functions, and 7 convenience functions). This was done by analyzing the use case and the customers' requirements for a smart trunk system. 18 new functions were derived via creative ideation codes. In addition, a scientific analysis method is proposed for product quality attributes and the strength of customer satisfaction. Using the Kano methodology, 25 functions were classified into quality attributes: 18 attractive qualities, 3 one-dimensional qualities, and 4 complex qualities, which are combinations of one-dimension qualities and must-have qualities. The functions that have one-dimensional quality and complex qualities were found to have higher customer ratings than the functions that have attractive qualities. Based on this, enterprises could effectively reduce customer complaints and enhance customer satisfaction.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.2
• /
• pp.51-59
• /
• 2019

There is increasingly more research focusing on the application of FRP reinforcing bars as an alternative material for steel reinforcing bars, but most such research look at short term behavior of FRP reinforced structures. In this study, the microscopic analysis and tensile behavior of Basalt and Glass FRP bars under freezing-thawing and alkaline conditions were experimentally evaluated. After 100 cycles of the freezing and thawing, the tensile strength and elastic modulus of FRP bars decreased by about 5%. In the case of microstructure of FRP bars during the initial 20 days, no significant damages of FRP bar sections were found under $20^{\circ}C$ alkaline solution; however, the specimens immersed in $60^{\circ}C$ alkaline solution were found to experience resin dissolution, fiber damage and the separation of the resin-fiber interface. In the alkaline environment, the strength decrease of about 10% occurred in the environment at $20^{\circ}C$ for 100 days, but the tensile strength of FRPs exposed for 500 days decreased by 50%. At temperature of $40^{\circ}C$ and $60^{\circ}C$, an abrupt decrease in the strength was observed at 50 and 100 days. Especially, the tensile strength decrease of Basalt fiber Reinforced Polymer bars showed more severe degradation due to the damage caused by dissolution of resin matrix and fiber swelling in alkaline solution. Therefore, in order to improve the long-term performance of the surface braided FRPr reinforcing bars, surface treatment is required to ensure alkali resistance.

• Journal of Technology Innovation
• /
• v.27 no.2
• /
• pp.37-71
• /
• 2019

How has the passenger car's architecture evolved? In the meantime, the discussions on the car architecture have been mixed, i.e., integral, modular, and the coexistence of two types. Therefore, in this study, we aim to develop two indices can measure the degree of modularization of passenger car and its all modules using global trade data. By applying the indices to the framework of architecture positioning that reflects the hierarchical structure of a product, we examined that the degree of modularization of the passenger car architecture has been enhanced. Meanwhile, the degree of modularization differs across the modules that make up the car. Specifically, we observed the higher degree of modularization in front-end, cockpit and seat modules. Whereas, we found that body module had a relatively low degree of modularization. In particular, we observed that the platform of passenger car has notably modularized due to carmakers' efforts to achieve model diversification and reduction of cost and period in new product development at the same time. Interestingly, we showed that three modules, i.e., engine, chassis (relatively less modularized), and transmission (relatively highly modularized), had a different level of modularization, even if they commonly make up the platform. We contribute to the suggestion for analytical approaches that examine the degree of modularization and its progress longitudinally. In addition, we propose the necessity of decomposition of a system into elements in a study of product architecture, considering the possibly distinctive progress of modularization across the elements.

• Journal of the Korea Institute of Building Construction
• /
• v.19 no.3
• /
• pp.201-207
• /
• 2019

In this study, the direct tensile properties of amorphous metallic fiber-reinforced cement based composites according to the strain was evaluated. A thin plate-shape amorphous metallic fiber with 15mm and 30mm in length was used. And fiber-reinforced cement based composites were prepared with contents of 1.0, 1.5, 2.0%. The direct tensile test was conducted under the conditions of $10^{-6}/s(static)$ and $10^1/s(dynamic)$ strain rate. As a results, amorphous metallic fiber with a length of 15mm was observed in pull-out behavior from the cement matrix because of the short fiber length and large portion of mixed fiber. On the other hand, amorphous metallic fiber with a length of 30mm were not pulled out from matrix because the bonding force between the fiber and matrix was large due to rough surface and large specific surface area. However, fracture occurred because thin plate shape fibers were vulnerable to shear force. Tensile strength, strain capacity and toughness were improved due to the increase in the fiber length. The dynamic increase factor of L15 was larger that of L30 because the bonding performance of the fiber-matrix interface is significantly affected by the strain rate.

• KIPS Transactions on Software and Data Engineering
• /
• v.8 no.5
• /
• pp.213-222
• /
• 2019

Determining the meaning of a keyword in a speech dialogue system is an important technology for the future implementation of an intelligent speech dialogue interface. After extracting keywords to grasp intention from user's utterance, the intention of utterance is determined by using the semantic mark of keyword. One keyword can have several semantic marks, and we regard the task of attaching the correct semantic mark to the user's intentions on these keyword as a problem of word sense disambiguation. In this study, about 23% of all keywords in the corpus is manually tagged to build a semantic mark dictionary, a synonym dictionary, and a context vector dictionary, and then the remaining 77% of all keywords is automatically tagged. The semantic mark of a keyword is determined by calculating the context vector similarity from the context vector dictionary. For an unregistered keyword, the semantic mark of the most similar keyword is attached using a synonym dictionary. We compare the performance of the system with manually constructed training set and semi-automatically expanded training set by selecting 3 high-frequency keywords and 3 low-frequency keywords in the corpus. In experiments, we obtained accuracy of 54.4% with manually constructed training set and 50.0% with semi-automatically expanded training set.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.6
• /
• pp.10-16
• /
• 2020

Deterioration of reinforced concrete structure caused by chloride ingress is the main issue and regrading this, many studies have been investigated with both experiments and computational modelling. In addition to chloride diffusion, chloride sorption should be considered as a chloride transport mechanism in concrete structure and cracks formed in concrete structures are the main variable to evaluate the performance of the structures. In this study, after making two types of cracks width (0.1 and 0.3 mm) in reinforced concretes, chloride absorption tests were performed. Weight change and colour change using 0.1 AgNO3 solution from the samples were performed to measure chloride ingress. Image processing was also carried out to quantify range of colour change in carck face. From the result, it were confirmed that the amount of chloride absorption increases with exposure time and increasing crack width, and chlorides reached at steel depth within 1 hour. It would be possible that chloride can move through interface bewteen steel and concrete, thereby further study regarding this is required.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.10
• /
• pp.1331-1340
• /
• 2020

Object detection in maritime means that the captain detects floating objects that has a risk of colliding with the ship using the computer automatically and as accurately as human eyes. In conventional ships, the presence and distance of objects are determined through radar waves. However, it cannot identify the shape and type. In contrast, with the development of AI, cameras help accurately identify obstacles on the sea route with excellent performance in detecting or recognizing objects. The computer must calculate high-volume pixels to analyze digital images. However, the CPU is specialized for sequential processing; the processing speed is very slow, and smooth service support or security is not guaranteed. Accordingly, this study developed maritime object detection software and implemented it with FPGA to accelerate the processing of large-scale computations. Additionally, the system implementation was improved through embedded boards and FPGA interface, achieving 30 times faster performance than the existing algorithm and a three-times faster entire system.

• Journal of Advanced Navigation Technology
• /
• v.25 no.1
• /
• pp.68-77
• /
• 2021

In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.