• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.98-115
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• 2012

New trend called ubiquitous leads the recent business by standardization and integration. It should be the main issue how to guarantee the integration and accountability on each business, especially in mission critical system which is mainly supported by M2M (Machine to Machine) control mechanism. This study is from the analysis of digital forensics case study that is from the M2M Sensing Control Mechanism problem of the "Imjin River" case in 2009, where a group of family is swept away to death by water due to M2M control error. The ubiquitous surroundings bring the changes in the field of criminal investigation to real time controls such as M2M systems. The needs of digital forensics on M2M control are increasing on every crime scene but we suffer from the lack of control metrics to get this done efficiently. The court asks for more accurately analyzed results accounting high quality product development design. Investigators in the crime scene need real-time analysis against the crime caused by poor quality of mission critical systems. It seems to be every need of Real-Time-Enterprise, so called ubiquitous society on the case. We try to find the efficiency and productivity in discovering non-functional design defects in M2M convergence products focusing on three metrics in study model with quick implementation. Digital forensics system in present status depends on know-how of each investigator and is hard to expect professional analysis on every field. This study set up a hypothesis "Co-working of professional investigators on each field will qualify Performance and Integrity" especially in mission critical system such as M2M and suggests "Online co-work analysis model" to efficiently detect and prevent mission critical errors in advance. At the conclusion, this study proved the statistical research that was surveyed by digital forensics specialists around M2M crime scene cases with quick implementation of dash board.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1119-1127
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• 2012

The one of features of M2M communications, which are recently attracted attention as a future business of mobile communications, is that there is a large number of devices compared with traditional communication services. Hence, the control signal that are generated by the M2M devices may cause a significant congestion in the network and in order to solve this problem, a standardization is progressing for reducing the redundant signaling by managing M2M devices as a group in 3GPP standardization. In this paper, we propose a method of group based mobility management by managing M2M devices that have the same mobility as a group. In the proposed method, M2M devices that have the same mobility are grouped by the Mobility Management Entity (MME) and the MME elects a group header among the M2M devices in the group. Then, the group header performs the Tracking Area Update (TAU) on behalf of the group members to reduce the signaling overhead of mobility management. With the proposed method, we can achieve 80% decrease of the signaling overhead of mobility management compared with the case where each M2M device individually performs its TAU procedure.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.201-210
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• 1999

One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. Therefore, a key requirement for improving te machining accuracy and product quality is to reduce the geometric and thermal errors of machine tools. This study models geometric error for error analysis and develops on-machine measurement system by which the volumetric erors are measured. The geometric error is modeled using form shaping function(FSF) which is defined as the mathematical relationship between form shaping motion of machine tool and machined surface. The constant terms included in the error model are found from the measurement results of on-machine measurement system. The developed on-machine measurement system consists of the spherical ball artifact (SBA), the touch probe unit with a star type stylus, the thermal data logger and the personal computer. Experiments, performed with the developed measurement system, show that the system provides a high measuring accuracy, with repeatability of ${\pm}2{\mu}m$ in X, Y and Z directions.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.57-60
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• 2021

Industry 4.0 is continuous automation by applying the latest smart technologies to traditional manufacturing industries. It means that large-scale M2M (Machine-to-Machine) communication and IoT (Internet of Things) technologies are well integrated to build efficient production systems by analyzing and diagnosing various issues without human intervention. Edge computing is widely used for M2M services that handle real-time interactions between devices at industrial machinery tool sites. Here, secure data transmission is required while interacting. Thus, this paper focused on a method of creating and maintaining secret key and security tag used for message authentication between end-devices and edge-device.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.131-139
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• 2023

High-dose I-131 used for the treatment of thyroid cancer causes localized exposure among radiology technologists handling it. There is a delay between the calibration date and when the dose of I-131 is administered to a patient. Therefore, it is necessary to directly measure the radioactivity of the administered dose using a dose calibrator. In this study, we attempted to apply machine learning modeling to measured external dose rates from shielded I-131 in order to predict their radioactivity. External dose rates were measured at 1 m, 0.3 m, and 0.1 m distances from a shielded container with the I-131, with a total of 868 sets of measurements taken. For the modeling process, we utilized the hold-out method to partition the data with a 7:3 ratio (609 for the training set:259 for the test set). For the machine learning algorithms, we chose linear regression, decision tree, random forest and XGBoost. To evaluate the models, we calculated root mean square error (RMSE), mean square error (MSE), and mean absolute error (MAE) to evaluate accuracy and R² to evaluate explanatory power. Evaluation results are as follows. Linear regression (RMSE 268.15, MSE 71901.87, MAE 231.68, R² 0.92), decision tree (RMSE 108.89, MSE 11856.92, MAE 19.24, R² 0.99), random forest (RMSE 8.89, MSE 79.10, MAE 6.55, R² 0.99), XGBoost (RMSE 10.21, MSE 104.22, MAE 7.68, R² 0.99). The random forest model achieved the highest predictive ability. Improving the model's performance in the future is expected to contribute to lowering exposure among radiology technologists.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.24-30
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• 1998

Strength and displacement of jig body in index machine utilized for multiprocess machining such as drilling, boring and tapping, etc, at the same time were analyzed by the use of finite element analysis soft ware ANSYS 5.2A. The whole geometry was constructed by 4048 elements and 7016 nodes employing 8 node brick element. The analyses were carried out on five loading cases combining vertical and horizontal machining to simulate the case occurring large displacement and the one occurring small displacement one and provided following conclusions. (1) Jig body had sufficient strength because its safety factor was 6.95 even in the most severe loading case. (2) The largest displacement in Z direction was 549 m and that in radial direction was 43.7 m. (3) In order to reduce the displacement, vertical machining rather than horizontal or two or three processes should be adopted in the same station. (4) Alternate change of horizontal machining direction at consecutive stations can reduce the displace ment. (5) The dimension of the slider should be increased to reduce the displacement by the tolerance in the sliding part. (6) A bypass idle piston head needs to be installed to give a counterpart supporting load from opposite direction for a single horizontal machining case.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.3-9
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• 2014

We propose energy efficient transmit and receive strategies for nomadic M2M devices. Recently, communication applications consume more and more battery. Hence, the efficient battery management is becoming increasingly important. Turbo code as a channel coding is being widely used in many communication areas. Accordingly, the efficient energy management in using turbo code is an important issue. In this paper, we optimize joint transmit and receive energy for M2M devices pair. We first model the transmit energy and receive energy. Then, we develop the energy efficient transmit and receive strategies.

• Journal of Internet Computing and Services
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• v.15 no.1
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• pp.103-112
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• 2014

In recent years, the rapid diffusion of smart devices and growth of internet usage and social media has led to a constant production of huge amount of valuable data set that includes personal information, buying patterns, location information and other things. IT and Production Infrastructure has also started to produce its own data with the vitalization of M2M (Machine-to-Machine) and IoT (Internet of Things). This analysis study researches the applicable effects of Structured and Unstructured Big Data in various business circumstances, and purposes to find out the value creation method for a corporation through the Structured and Unstructured Big Data case studies. The result demonstrates that corporations looking for the optimized big data utilization plan could maximize their creative values by utilizing Unstructured and Structured Big Data generated interior and exterior of corporations.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.603-606
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• 2013

Machine to Machine (M2M) 통신은 수 많은 장비들이 우리 주변환경의 정보를 감지하여 상호간에 주고받는 방법을 활용한다. Third generation partnership project (3GPP)는 이러한 M2M 통신을 활용하여 유비쿼터스 환경과 자가인식형 서비스를 제공하려 하고 있다. 본 논문은 이러한 추세에 맞추어 새로운 개념의 통신인 3GPP M2M 통신의 시스템 구조, 특징들과 이에 대한 3GPP의 연구방향 등에 대한 튜토리얼로 사용될 수 있도록 하기 위해 작성되었다. 특히 M2M 통신에서의 특징들을 구체화하는 과정에서의 보안상 위협과 이에 대처하기 위한 요구사항들에 대해서 강조하였다. 이러한 보안상 위협을 제거하는 요구사항을 만족하면서 네트워크에 과부하를 가하지 않도록 하기 위한 그룹 기반의 최적화된 인증 프로토콜을 제안한다. 본 논문에서는 그룹을 기반으로 bilinear pairing을 사용하여 인증을 진행하며, 통신 딜레이를 줄이고 네트워크의 중심 장비에 과부하를 줄이기 위해 HSS(Home Subscriber Server)의 참여를 제한한 인증 및 키 동의 프로토콜을 제안하고, 이에 따른 연산 및 통신 오버헤드를 분석한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.669-672
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• 2011

최근 IT(Information Technology)와 타(他)산업 간의 융 복합이 촉진되면서 새로운 융합서비스로 사물지능 통신(M2M, Machine to Machine)이 차세대 지능형 인프라 기반의 핵심 서비스로 부각되고 있다. 사물지능 통신은 기존의 통신 인프라를 활용하여 사물정보의 수집, 가공, 처리를 통해 최종 서비스를 제공하는 기술 분야로 PHY, MAC, 라우팅에 대한 기술 이슈보다는 서비스 관점에서의 네트워크 아키텍처 정의와 기능, 서비스 플랫폼 간의 연동, M2M 단말과 네트워크 간의 인터페이스에 대한 연구가 진행 중이다. 본 논문에서는 사물지능통신 융합서비스를 사용자에게 보다 편리하게 제공하기 위한 기존 플랫폼 간의 연동을 위한 요구사항과 방안을 제안한다.