• Journal of Information Technology Services
• /
• v.17 no.2
• /
• pp.111-128
• /
• 2018

About 3.9 million apps and 24 primary categories can be approved on Apple iTunes Store. Making accurate categorization can potentially receive many benefits for developers, app stores, and users, such as improving discoverability and receiving long-term revenue. However, current categorization problems may cause usage inefficiency and confusion, especially for cross-attribution, etc. This study focused on evaluating the reliability of app categorization on Apple iTunes Store by using several rounds of inter-rater reliability statistics, locating categorization problems based on Machine Learning, and making more accurate suggestions about representative functionality stems for each primary category. A mixed methods research was performed and total 4905 popular apps were observed. The original categorization was proved to be substantial reliable but need further improvement. The representative functionality stems for each category were identified. This paper may provide some fusion research experience and methodological suggestions in categorization research field and improve app store's categorization in discoverability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.5
• /
• pp.39-44
• /
• 2011

Automatic fire alarm system is set up to automatically detect fire on buildings. Because of economic reasons, P-type receiver and a conventional type fire detector is normally used for automatic fire alarm system in Korea. Because early detection of fire is regarded as important, the need of finding technique of fire location increases. This paper is studied a method to improve a reliability and add a function of fire location detection on a conventional type fire detector and P-type receiver. Fire location is detected by a method that controller attached on the receiver and the detector is read with a time lag. A reliability of fire detection alarm system is improved with a method that false fire alarm is able to decrease using two different principle detector together. This paper is studied for basic data of improvement of low-cost addressable automatic fire alarm system.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.21 no.3
• /
• pp.383-388
• /
• 2011

This paper presents to study the accuracy improvement of the laser navigation using FIS(fuzzy inference system) and the reliability. As wireless guidance system, the top-mounted laser with the laser navigation can rotate $360^{\circ}$ with phototransistor or other optical sensors that read the return signal from reflectors mounted at the perimeter of the workspace. The type of major existing guidance systems is a wire guidance system. Because they have high accuracy and fast response time, they are used to most industries. However, their installation cost is very expensive and maintenance is very difficult because their sensors are placed approximately 1 inch below the ground or embedded in the floor. To solve those problems, the laser navigation was developed as a wire guidance system. It does not need to reconstruct a floor or ground. And it can reduce costs of installation and maintenance because changing the layout is easy. However, it is difficult to apply to an industrial field because it is easily affected by disturbances which cause loss and damage of data, and has slow respond time. Therefore, we study the accuracy improvement of the laser navigation. The proposed method is a correction method using reliability of the laser navigation. here, reliability is calculated by FIS which is designed with the analyzed characteristics of the laser navigation. For performance comparison, we use original position data form the laser navigation and position data corrected by original reliability from the laser navigation. In experimental result, we verified that the performance of the proposed method compared the others is improved by about 50% or more.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.265-268
• /
• 2004

In this paper, we improved the reliability of a spiral spring in semi-auto sliding mechanism of mobile phones. In an semi-auto opening mechanism of mobile phone, the spring must have sufficient reliability such that the spring force does not reduce under a half of initial value after 100000 operations. Since the inner space of the mechanism is very small, it is difficult to design a spring having sufficient reliability. We designed a spiral spring satisfying such conditions and analyzed its elastic performances using finite element method.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1472-1478
• /
• 2009

The domestic power distribution system is operating in an open loop mode; however, it already has a loop structure. Power distribution systems must be changed for bi-directions power supply for smart networks due to a changing of paradigm in electric power industry. The simplest bi-directions distribution networks can make it closing of normally open switch. However, bi-directions power supply is very difficulty to be operated and there are many parts which it must study. This paper presented various models that are able to change a radial system for loop structures. Further, we compared the reliability index for each model by evaluating the amount of improvement reliability required in radial power distribution system. In addition, we calculated CIC(Customer Interruption Cost) for each model by comparing and analyzing.

• International Journal of Aeronautical and Space Sciences
• /
• v.4 no.2
• /
• pp.37-50
• /
• 2003

A next generation small satellite HAUSAT-1, the first picosatellite developed in Korea, is being developed as one of the international CubeSat program by Space System Research Lab. of Hankuk Aviation University. A fault-tolerant incremental design methodology has been addressed in this paper. In this study, the effect of system redundancy on reliability was in details analyzed in accordance with the implementation of fault-tolerant system. Four different system recovery levels are proposed for HAUSAT-1 fault-tolerant system optimization. As a result, the HAUSAT-1 fault-tolerant system architecture design and reliability analysis has acquired about 11% reliability improvement.

• Journal of Applied Reliability
• /
• v.11 no.4
• /
• pp.419-432
• /
• 2011

In order to distribute machinery to European Union, it is mandatory to get CE marking to ensure the machinery is safe and reliable. The EHSR(Essential Health and Safety Requirements) of the EC Machinery Directive requires the machinery to be designed and manufactured to prevent from any dangerous situation. This study presents a case of CE Certification in Back Cover Nut Insert Machine and introduces an improvement method of product safety and reliability. This study also presents how to eliminate the deficiencies in design and manufacturing, and the process of applying EHSR for CE Marking.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.891-894
• /
• 1999

According to increasing the integration of the device, there are important consideration about the improvement of the reliability in the product. To improve the reliability of the device, the test parameters and test time are increased. There are no pin-to-pin short test and pin-to-pin leakage test in the present test items to analysis the characteristics and reliability of the device. The purpose of the paper is to model the pin-to-pin phenomenon and propose to modify the test method present and to test the new pin-to-pin DC parameters. These modified and additive test items are applied to product test and confirmed to improve the reliability of product test.

• Journal of Sensor Science and Technology
• /
• v.6 no.2
• /
• pp.131-136
• /
• 1997

The ISFET(ion sensitive field effect transistor), a semiconductor ion sensor, has many advantages over conventional ion sensors. Various single-sensor type ISFET pH-meters have been developed. However, they could not be applied in fields because their performances are directly affected by the sensor condition. With only one sensor, the system could be easily damaged from environmental factors, and reliability of it is decreased. Therefore, a 4-channel PH-meter system is proposed to improve the reliability of ISFET pH-meter. It has 4 ISFETS as ion sensor, and a software which contains a new calibration and measurement algorithm appropriate to the system. The reliability of the system was proved by measuring hydrogen ion concentration in the pH standard solutions and buffer solutions.

• Journal of Korea Society of Industrial Information Systems
• /
• v.7 no.2
• /
• pp.33-39
• /
• 2002

Accelerated life testing of a car is used to get information quickly on its life distribution. Test cars are no under severe conditions and fail sooner than under usual conditions. A model is fitted to the accelerated failure times and then extrapolated to estimate the life distribution under usual conditions. This paper presents an accelerated test md the reliability growth theory, and applies it to some subsystems of cars during their prototype and pilot testing. The data presented illustrates explicitly the prediction of the reliability growth in the product development cycle. The application of these techniques is a part of the product assurance function that plays an important role in product reliability improvement.