• The Journal of Society for e-Business Studies
• /
• v.23 no.1
• /
• pp.1-22
• /
• 2018

The value chain has been utilized as a strategic tool to improve competitive advantage, mainly at the enterprise level and at the industrial level. However, in order to conduct value chain analysis at the enterprise level, the client companies of the parent company should be classified according to whether they belong to it's value chain. The establishment of a value chain for a single company can be performed smoothly by experts, but it takes a lot of cost and time to build one which consists of multiple companies. Thus, this study proposes a model that automatically classifies the companies that form a value chain based on actual transaction data. A total of 19 transaction attribute variables were extracted from the transaction data and processed into the form of input data for machine learning method. The proposed model was constructed using the Random Forest algorithm. The experiment was conducted on a automobile parts company. The experimental results demonstrate that the proposed model can classify the client companies of the parent company automatically with 92% of accuracy, 76% of F1-score and 94% of AUC. Also, the empirical study confirm that a few transaction attributes such as transaction concentration, transaction amount and total sales per customer are the main characteristics representing the companies that form a value chain.

• Journal of IKEEE
• /
• v.19 no.3
• /
• pp.311-318
• /
• 2015

This dissertation proposes method for development technology of voice and SMS(Short Message Service) alarming system based on modbus protocol. The proposed technology is composed of the following 3 stages; hardware development based on microprocessor, development of input and output driver for modem, mp3 decoder, making modbus protocol stack. In the stage of hardware development based on microprocessor, we develop hardware which receives alarm from modbus master and transmit sms message, play mp3. In the stage of development of input / ouput device driver such as modem, mp3 decoder, we develop program which control each devices. In the stage of making modbus protocol stack, voice and sms alarm system is made for receiving alarm via modbus protocol. To evaluate performance of proposed technology, we issued alarm to voice and sms alarming system on purpose. As a result, response speed of detecting alarm was 10.7ms, communication distance was 1.2Km, operating temperature was from $-25^{\circ}C$ to $70^{\circ}C$, we confirmed supporting modbus protocol. And we verified that proposed voice and sms alarming system in the thesis has a performance to be used as an industrial building alarming system.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.4
• /
• pp.79-86
• /
• 2016

Physical layer security is cryptography technique to protect information by using physical nature of signals. Currently, many works on physical layer security have been actively researching while those researching models still have some problems to be solved. Eavesdropper does not share its channel state information with legitimate users to hide its presence. And when node transmits signal, hardware impairments are occurred, whereas many current researches assume that node model is ideal node and does not consider hardware impairments. The main features and contributions of this paper to solve these problems are as follows. First, our proposed system model deploys torch node around legitimate user to obtain channel state information of eavesdropper and considers hardware impairments by using channel state information of torch node. Second, we derive closed-form expression of intercept probability for the proposed system model. The results of the performance evaluation through various simulations to find out the effects on proposed system model in physical layer security show that imperfect channel state information does not effect on intercept probability while imperfect node model effects on intercept probability, Ergodic secrecy capacity and secrecy capacity.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.1
• /
• pp.95-110
• /
• 2014

The purpose of this research is to further investigate the influence of partnership between with the mediator effect of the social business on the outcome of SCM. IT technology fusion electronic tags, mobile phone, such as cloud computing is also activated in supply chain management of recently, business is faster, if social business is applied here that are smarter, customers or suppliers, there may be communication directly and to further improve the relationship partnership. 150 questionnaires were sent to companies that have introduced SCM to their systems and are operating it. Among 150 questionnaires, 127 collected data were analyzed excluding incomplete 23 data. Statistical methods used in this study were frequency analysis, factor analysis, reliability analysis, t-test, ANOVA, path analysis, Scheffe test and Sobel test with Amos 18.0. and SPSS 21.0. The analytical results are as follows. First, the more the reliability, information share, continuous transaction, effects on the social business are getting higher, the interdependence has little impact on it. Second, the impact on the outcome of SCM, partnerships between companies, showed a significant influence the reliability, the share of information, the continuous transaction, but the interdependence was analysed as an uninfluential factor. Third, the social business is analyses to have a mediator effect in relationship between the partnership and the outcome of SCM.

• Proceedings of the KSRS Conference
• /
• 2008.10a
• /
• pp.220-223
• /
• 2008

A camera system for the satellite application performs the mission of observation by measuring radiated light energy from the target on the earth. As a development stage of the system, the signal level analysis by estimating the number of electron collected in a pixel of an applied CCD is a basic tool for the performance analysis like SNR as well as the data path design of focal plane electronic. In this paper, two methods are presented for the calculation of the number of electrons for signal level analysis. One method is a quantitative assessment based on the CCD characteristics and design parameters of optical module of the system itself in which optical module works for concentrating the light energy onto the focal plane where CCD is located to convert light energy into electrical signal. The other method compares the design\ parameters of the system such as quantum efficiency, focal length and the aperture size of the optics in comparison with existing camera system in orbit. By this way, relative count of electrons to the existing camera system is estimated. The number of electrons, as signal level of the camera system, calculated by described methods is used to design input circuits of AD converter for interfacing the image signal coming from the CCD module in the focal plane electronics. This number is also used for the analysis of the signal level of the CCD output which is critical parameter to design data path between CCD and A/D converter. The FPE(Focal Plane Electronics) designer should decide whether the dividing-circuit is necessary or not between them from the analysis. If it is necessary, the optimized dividing factor of the level should be implemented. This paper describes the analysis of the electron count of a camera system for a satellite application and then of the signal level for the interface design between CCD and A/D converter using two methods. One is a quantitative assessment based on the design parameters of the camera system, the other method compares the design parameters in comparison with those of the existing camera system in orbit for relative counting of the electrons and the signal level estimation. Chapter 2 describes the radiometry of the camera system of a satellite application to show equations for electron counting, Chapter 3 describes a camera system briefly to explain the data flow of imagery information from CCD and Chapter 4 explains the two methods for the analysis of the number of electrons and the signal level. Then conclusion is made in chapter 5.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.42 no.1
• /
• pp.29-34
• /
• 2005

The wound induction motor can provide high starting torque and reduced starting current simultaneously by inserting large resistor externally when starting. And this technique is one of the well known methods among the induction motor starting methods and generally used for heavy load starting such as crane and cement factories. The conventional PI controller has been widely used in industrial application due to the simple control algorithm and is generally used for control of current torque, position, and speed for the wound induction motor drive system. However, the conventional control system for wound induction motor may result in poor performance because sensors have to be used but are often limited by the environmental condition. Recently, to overcome these problems, many sensorless vector control methods for the wound induction motor have been studied. This paper presents a MRAS method for sensorless vector control of the wound induction motor drive. In the conventional MRAS method, in low frequency, the stator resistance variation may result in poor performance. Therefore, this paper presents a MRAS method with stator and rotor resistance tuning for sensorless vector control of the wound induction motor to overcome several shortages of the conventional MRAS caused by parameter variation and to enhance the robustness of the sensorless vector control. The validity and effectiveness of the proposed method is verified through digital simulation.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.5
• /
• pp.40-49
• /
• 2008

A Frequency synthesizer for mobile-DTV applications is implemented using $0.18{\mu}m$ CMOS process with 1.8V supply. PMOS transistors are chosen for VCO core to reduce phase noise. The measurement result of VCO frequency range is 800MHz-1.67GHz using switchable inductors, capacitors and varactors. We use varactor bias technique for the improvement of VCO gain linearity, and the number of varactor biasing are minimized as two. VCO gain deterioration is also improved by using the varactor switching technique. The VCO gain and interval of VCO gain are maintained as low and improved using the VCO frequency calibration block. The sigma-delta modulator for fractional divider is designed by the co-simualtion method for accuracy and efficiency improvement. The VCO, PFD, CP and LF are verified by Cadence Spectre, and the sigma-delta modulator is simulated using Matlab Simulink, ModelSim and HSPICE. The power consumption of the frequency synthesizer is 18mW, and the VCO has 52.1% tuning range according to the VCO maximum output frequency. The VCO phase noise is lower than -100dBc/Hz at 1MHz at 1MHz offset for 1GHz, 1.5GHz, and 2GHz output frequencies.

• Journal of IKEEE
• /
• v.18 no.4
• /
• pp.544-551
• /
• 2014

This paper suggests an algorithm to measure low-level radiation by radiation measuring devices, and the other algorithm to improve reaction speed of the device to better respond to dramatic changes in radiation amount. The former algorithm to improve the accuracy of measuring low-level radiation takes advantage of a dual window radiation measurement method which is based on accumulated average of pulses gathered by a radiation measuring sensor. The latter algorithm is to enhance reaction speed of a measuring device to more sensitively react to dramatic changes in radiation amount by adopting a dual window radiation measurement method which analyzes data patterns newly put into for six seconds. To verify the suggested algorithms, a hardware-which consists of sensor and high-voltage generator, controller, charger and power supply circuit, wireless communication part, and display part-was used. Tests conducted on the dual window radiation measurement method as used in the suggested algorithm have proved that accuracy improves to measure low-level radiation of 5uSv/h, and linearity also gets better. Other tests were conducted to see whether the suggested algorithm enhances the reaction speed of a radiation measuring device so that the device responds better to dramatically changing radiation amount. The experimental results have shown meaningful changes in numbers after six seconds. Therefore, the conclusions are made that the algorithm enhances the reaction speed of the device.

• Journal of Advanced Navigation Technology
• /
• v.15 no.2
• /
• pp.287-297
• /
• 2011

As electronic mails are being widely used for facility and speedness of information communication, as the amount of spam mails which have malice and advertisement increase and cause lots of social and economic problem. A number of approaches have been proposed to alleviate the impact of spam. These approaches can be categorized into pre-acceptance and post-acceptance methods. Post-acceptance methods include bayesian filters, collaborative filtering and e-mail prioritization which are based on words or sentances. But, spammers are changing those characteristics and sending to avoid filtering system. In the case of Korean, the abnormal usages can be much more than other languages because syllable is composed of chosung, jungsung, and jongsung. Existing formal expressions and learning algorithms have the limits to meet with those changes promptly and efficiently. So, we present an methods for recognizing Korean abnormal language(Koral) to improve accuracy and efficiency of filtering system. The method is based on syllabic than word and Smith-waterman algorithm. Through the experiment on filter keyword and e-mail extracted from mail server, we confirmed that Koral is recognized exactly according to similarity level. The required time and space costs are within the permitted limit.

• Korean Journal of Materials Research
• /
• v.11 no.1
• /
• pp.27-33
• /
• 2001

The growth characteristics of 4-fold grain which was appeared in KLN deposition on $Pt/Ti/SiO_2/Si(100)$ substrate was studied by varying process variables. Substrate temperature, sputtering pressure, rf power were selected as process variables, and experiment was carried out near optimum fabrication condition. When using K and Li enriched target, the optimum fabrication conditions were substrate temperature of $600^{\circ}C$, sputtering pressure of 150mTorr, rf power of 100 W and its surface morphology is sensitively varied by small deposition condition changes. KLN is composed of elements which have large difference of boiling point. And it is difficult to fabricate thin film at high temperature and high vacuum deposition condition. Furthermore the phenomenon during deposition process can not be explained by using Thorton's model which explains the relation between thin film structure and melting point of thin film materials. These phenomenon can be explained using boiling point of elements which consist of thin film material.