• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.20-29
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• 2014

As construction projects increase their complexity, variety, and scale, various recognition applications (such as RFID, bar-code etc.) have been tried for managing material effectively in construction projects. However, existing recognition applications for construction material management have some limitations that cause additional works (such as attaching RFID tag), additional cost (labor cost, recognition device cost, etc.), and cognitive impairment of workers. Therefore, this study proposed a character recognition technology as an alternative of previous recognition technologies such as RFID, bar-code, etc. The technical feasibility of proposed technology was validated by three recognition tests. Additionally, this study proposed code the structure to manage materials using the character recognition technology. The effects of character recognition technology are presented by comparing with existing RFID-based logistics processes.

• Journal of Satellite, Information and Communications
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• v.8 no.2
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• pp.94-98
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• 2013

A report of security problems and simultaneous operation limits of Standard tone currently used for FTS introduces the development of a next generation FTS. In this paper, BER performance by modulations and channel coding methods for EFTS are compared. Simulation results show that coherent modulations have better BER performance than noncoherent modulations. However the environments of a lunching vehicle may cause serious problems in achieving and maintaining synchronization and the increasing complexity of coherent systems also increases reliability problems. Therefore noncoherent systems are suitable for FTS even though BER performace of noncoherent systems is lower than coherent systems. Noncoherent DPSK has better BER performance than noncoherent CPFSK. However the PEP of noncoherent DPSK is 0.8dB higher than noncoherent CPFSK. Therefore a transmitter of noncoherent DPSK has more output power than noncoherent CPFSK. Convoltional code has better BER performance than RS code. However RS code has a tendency of steeply decreasing BER near the wanted $E_b/N_0$.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.83-92
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• 2009

Complicated business logic makes program complexity more complicated. It's inevitable that the program must undergo reengineering processes all the way of in its lifetime. Hot spot analysis that has diverse purposes is getting an important question more and more. As a rule, reengineering process is done by UML model-based approach to analyze the legacy system. The smallest fragment of targets to be analysed is unit, that is function or class. Today's software development is to deal with huge change of software product and huge class including heavy quantity of LOC(Lines Of Code). However, analysis of unit is not precise approach process for reliable reengineering consequence. In this paper, we propose very precise hot spot analysis approach using Aspect-Oriented Programming languages, such as AspectJ. Typically the consistency between UML and source is needed code to redefine the modified library or framework boundaries. But reengineering approach using AOP doesn't need to analyze UML and source code. This approach makes dynamic event log data that contains detailed program interaction information. This dynamic event log data makes it possible to analyze hot spot.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1056-1063
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• 2008

This paper describes an efficient design of a multi-standard Viterbi decoder that supports multiple constraint lengths and code rates. The Viterbi decoder is parameterized for the code rates 1/2, 1/3 and constraint lengths 7,9, thus it has four operation nodes. In order to achieve low hardware complexity and low power, an efficient architecture based on hardware sharing techniques is devised. Also, the optimization of ACCS (Accumulate-Subtract) circuit for the one-point trace-back algorithm reduces its area by about 35% compared to the full parallel ACCS circuit. The parameterized Viterbi decoder core has 79,818 gates and 25,600 bits memory, and the estimated throughput is about 105 Mbps at 70 MHz clock frequency. Also, the simulation results for BER (Bit Error Rate) performance show that the Viterbi decoder has BER of $10^{-4}$ at $E_b/N_o$ of 3.6 dB when it operates with code rate 1/3 and constraints 7.

• Journal of the Korea Society of Computer and Information
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• v.27 no.4
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• pp.231-239
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• 2022

In this paper, I analyze the difficulties of web service development education for non-IT majors through the Q&A of students posted in the k-mooc lecture, and propose methods to improve them. Through Q&A analysis, it was confirmed that non-majors mainly had difficulties in using unfamiliar tools, cost of cloud service, setting up server environment, and writing code while taking web service development courses. To solve this problem, I propose a method to reduce the server cost problem and the complexity of the server environment by using BaaS(Backend as a Service), which is one of the cloud service models. It also shows that it is possible to reduce the length of code that needs to be written at once by using the React library to modularize long code into smaller units. Finally, I propose an improvement plan that even non-IT majors can easily learn by implementing a web application that works by using the design output obtained by using Figma.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.419-426
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• 2012

A transient, three-dimensional, two-phase flow analysis code, CUPID, has been developed in KAERI. In this work, we performed a preliminary analysis using the CUPID code to investigate the thermal-hydraulic behavior of the moderator in the Calandria vessel of a CANDU reactor. At first, we validated the CUPID code using the three experiments that were performed at Stern Laboratories Inc. To avoid the complexity to generate computational mesh around the Calandria tube bundles, a porous media approach was applied for the region. The pressure drop in the porous media zone was modeled by an empirical correlation. The results of the calculations showed that the CUPID code can predict the mixed flow pattern of forced and natural convection inside the Calandria vessel very well. Thereafter, the analysis was extended to a two-phase flow condition. Also, the local maximum temperature in the Calandria vessel was plotted as a function of the injection flow rate, which may be utilized to predict the local subcooling margin.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10A
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• pp.980-989
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• 2002

In this paper, we have proposed the sectorization method of the adaptive sector antenna and the new receiver structure for the CDMA wireless multi-media communication which uses multi-code and single-code. The sectorization and average BER performance of the adaptive sector antenna, which employs the proposed sectorization method, are obtained through simulation. The simulation results have shown that the sizes of sectors are properly controlled according to the distribution of the load and that the BER performance of the adaptive sector antenna is enhanced much more than that of the fixed sector antenna. Also, we have proposed two receivers, which are different from the positions to detect multi-code signals, for the multi-media communication. Each receiver has a simple cancellation scheme and two adaptive sector antennas, which are called the 1st adaptive sector antenna and the 2nd adaptive sector antenna, respectively. In this paper, the average BER performances of the receivers are compared through simulation. As the results of the simulation, we have recognized that all user' BER performances are greatly dependent on the positions to detect the multi-code signals. When we consider both system complexity and terget BERs of signals, we have concluded that the receiver, which detect multi-code signals in the 1st and the 2nd adaptive sector antenna, is appropriate for the CDMA wireless multi-media communication systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.3A
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• pp.172-178
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• 2012

This paper studies the application of a fuzzy-ARTMAP (FAM) neural network to multi-user detector (MUD) for direct sequence (DS)-code division multiple access (CDMA) system. This method shows new solution for solving the problems, such as complexity and long training, which is found when implementing the previously developed neural-basis MUDs. The proposed FAM based MUD is fast and easy to train and includes capabilities not found in other neural network approaches; a small number of parameters, no requirements for the choice of initial weights, automatic increase of hidden units, no risk of getting trapped in local minima, and the capabilities of adding new data without retraining previously trained data. In simulation studies, binary signals were generated at random in a linear channel with Gaussian noise. The performance of FAM based MUD is compared with other neural net based MUDs in terms of the bit error rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.965-983
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• 2014

Concurrent behaviors of multithreaded programs cannot be described effectively by automata-based models. Thus, concurrent program intrusion attempts cannot be detected. To address this problem, we proposed the process algebra-based detection model for multithreaded programs (PADMP). We generate process expressions by static binary code analysis. We then add concurrency operators to process expressions and propose a model construction algorithm based on process algebra. We also present a definition of process equivalence and behavior detection rules. Experiments demonstrate that the proposed method can accurately detect errors in multithreaded programs and has linear space-time complexity. The proposed method provides effective support for concurrent behavior modeling and detection.

• Journal of Korea Society of Industrial Information Systems
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• v.2 no.2
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• pp.219-228
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• 1997

The Fano metric is the maximum likelihood decoding choice for convlutional code for binary symmetric channel. The Fano metric assumes that it has previous knowledge of channel error probability. However, the bit errors in real channel occur in bursts and the channel error probability can not be known exactly. Thus, the Fano metric is not the maximum likelihood choice for bursty-noise channel. In this paper universal metri which dose not require the previous knowlege of the channel transition probability is used for sequential decoding. It is shown that the complexity of the universal is much less than that of the Fano metric bursty-noise channel, since it is estimated on a branch by branch basis.