?Proposal of an attribute-based communication system A case of UNDERGROUND MINING ENVIRONMENT IN RWANDA Author: Supervisor: NYIRINGABO CHRISTIAN TERUAKI YOKOYAMA A thesis submitted in fulfillment of the requirements for the Degree of Master of Science in Information Systems KOBE INSTITUTE OF COMPUTING GRADUATE SCHOOL OF INFORMATION TECHNOLOGY JULY 20, 2018Abstract of the thesisUnderground mines are usually vast labyrinths that employ many people working on an area of ??several square miles and it is associated with several environmental hazards that cause an impact on mine workers safety and health. Therefore reliable and effective communication is essential for creating a safe, efficient and productive mine. This research targets the Rwandan mining sector where mineworkers die or left seriously injured due to fatal accidents caused by main landslides and we believe reliable and effective communication can play an important role in reducing such incidents.This research focuses on ensuring personnel safety by improving the current communication systems mainly in case of emergency by designing a system that allows fast message delivery between the surface base and underground miners.Currently, the communication is based on knowing phone numbers or email which restricts communication. By eliminating the need to know phone numbers or emails, an important barrier to communication is removed.
This research is a proposal of attribute-based communication which concept will help us make a new kind of communication which allow us to transmit a message to not a specific destination (phone number or email) but to Tag which can be dynamically changed according to the situation around the user.However, the proposed communication system is to be integrated into the application layer level (data sharing) after data collection(Ex: sensors) and data analysis(Monitoring center).This clearly defines that in this thesis, we will briefly suggest the type of infrastructure needed for our system integration without going into deep as our main focus is to propose a mine communication system which is able to reduce the excessive time required to locate key personnel in the underground in case of warnings or accidents as mining accidents can happen in minutes, so each minute wasted could be the difference between life and death.TABLE OF CONTENTSTable of Contents TOC o “1-3” h z u HYPERLINK l “_Toc521069693” Abstract of the thesis PAGEREF _Toc521069693 h 2 HYPERLINK l “_Toc521069694” CHAPTER 1 INTRODUCTION PAGEREF _Toc521069694 h 5 HYPERLINK l “_Toc521069695” 1.
1 BACKGROUND PAGEREF _Toc521069695 h 6AbstractTable of contentsList of figuresChapter 1 Introduction Background Problem statement Research purpose Paper structureChapter 2 Field research Frequent accident reasons Existing communication system The problem of the current communication system Chapter 3 Previous studies Wireless communication in underground mines Personal emergency device system Attribute-based communication Chapter 4 Proposed solution Proposed infrastructure Proposed solution System integration Chapter 5 System design and development System design System development A.Client side B. Server side C.DatabaseChapter 6 ExperimentChapter 7 Conclusion Summary Future workREFERENCES List of figuresFigure 1 Problem tree identifying our area of focus in this studyFigure 2.1 Frequent accidents reasonsFigure 2.2 Existing safety systemFigure 2.3 The problem of the current communication systemFigure 3.
1 PED schematic operationFigure 4.1 Proposed solution architectureFigure 4.2 Proposed message sending system interfaceFigure 4.3 Safety system architectureFigure 5.
1 Client-server architectureFigure 6.1 Web-based system front endFigure 6.2 Web interfaceFigure 6.
3 Database programmingFigure 6.4 SQLite database fileCHAPTER 1 INTRODUCTION1.1 BACKGROUNDCommunication is the activity related to the transmission of signals (data) for the information exchange. In underground mines, communication is extremely needed to ensure safety and productivity. The need to keep miner’s safety and increase mining production, demands more reliable communication methods, hence more and more research has been improving the technology from the beginning of the 20th century. Underground communication methods are lagging behind surface level communications, which has seen huge advancements, the latest being 4G technology. The less improved communication inside underground mines is not only due to general lack of interest in this area but also for the unfavorable environment.
Underground mining industries really need a full working communication system which may be capable to withstand in emergencies, as well as also to fulfill daily work requirements.This research targets Rwanda Mining sector which has the second largest export in the Rwandan economy. In 2017, the sector generated about $373.4 Million of foreign exchange. The sector plays an increasingly important role in the national economy and development framework. In its current second Economic Development and Poverty Reduction Strategy (EDPRS II), the Rwandan government identifies the mining sector as one of the selected priority areas to facilitate economic growth and fight poverty.
PROBLEM STATEMENTRwanda mining sector continues to face a fatal accident where mineworkers die or left seriously injured. The high number of the mine accidents occurred in the workplaces is caused by environmental hazards such as floods in the rainy season and mainly landslides. Mining activities have the potential hazard and risk that can impact the human being and environment, if not managed properly. If not managed properly it can result in losses, such as human injury or fatality, equipment and property damage, production or process delay, damage to the environment, and also the loss of profit.
Lack of modern safety systems including environmental monitoring, risk analysis and poor communication like warning messages are the root causes of the mentioned problem.In many Rwandan mining sites, the communication system is poor and unreliable or mostly non-existing, the only supervisor carries communication devices despite them not being involved in the underground activities which make the communication unreliable in case of warning or emergency. PROBLEM TREE114300114300Environment destructionProduction disruptionLoss of lifeMineworker’s accidents Lack of protection materialsUnskilled laborSafety gearsLack of experienceLow literacyPoorEnvironment monitoringPoor communicationPoor Risk analysisEnvironment hazards and risksEFFECTSCORE PROBLEMCAUSESEnvironment destructionProduction disruptionLoss of lifeMineworker’s accidents Lack of protection materialsUnskilled laborSafety gearsLack of experienceLow literacyPoorEnvironment monitoringPoor communicationPoor Risk analysisEnvironment hazards and risksEFFECTSCORE PROBLEMCAUSES Figure 1.Problem tree identifying our area of focus in this studyRESEARCH PURPOSETechnology is growing faster in Rwanda as the country decided to put its biggest investment in ICT, but the mining sector as one of the growing sector in Rwanda is yet to embrace technology as the majority of mines are artisanal mining and industrials mining are still dealing with production issues. However the government in partnership with the private sector are working on introducing technology in that sector by working with investors; and also by starting mining schools to provide knowledge to young professional about modern mining, hence the use of new technologiesThis research aim is to ensure mineworkers safety by improving the current communication systems mainly in case of emergency. This research is a proposal of communication systems that allow fast message delivery between the home base and the miners, the system will use text messages to inform others of hazards so that when disaster strikes, delays don’t cause unneeded deaths and injury. Mining accidents can happen in minutes, so each minute wasted could be the difference between life and death.The proposed solution in this thesis is a simple and quick communication system enabling mineworkers to share information regarding their safety and everyday work.
PAPER STRUCTUREThis part describes briefly all parts of the thesis in each chapter;Chapter 1: This chapter contains the background information about communication in mining environment in general and in Rwanda particularly, explains the existing problem through the problem statement and this thesis approach and purpose to solve the problem. Chapter 2: This chapter contains the field research outcome for more information about the current type of communication in the mining environment in Rwanda.Chapter 3: This chapter talks about related works that have been carried out in this field, type of technology used and challenges.Chapter 4: This chapter contains the proposed solution to solve the communication issue in the mining environment in Rwanda.Chapter 5: This chapter contains the design and development of the proposed solution for the mentioned problem.Chapter 6: This chapter contains figures showing experiments of our solution development. Chapter 7: This chapter covers the conclusion, discusses the limitation of our system and enlightens future researchers about the future works that can be made.
CHAPTER 2: FIELD RESEARCHThis field research was conducted on 13th December 2017 to 13th January 2018 for one month in Rwanda. The aim of this overseas research was to understand much more about the situation of mining and miners lifestyle.By conducting this overseas research, we distributed a questionnaire to the diver’s person working in the mining sector within the different part of the country.
We also had interviews with mine workers about the safety situation in mines and existing system used for communication purpose.Many responded negatively about the current warning system hence communication system used in that environment despite many environmental hazards like floods and landslides occurring and causing loss of life, fatal injuries, and loss of materials which decreases the production. The current communication way used is that; teams of mineworkers have leaders that carry communication devices(walkie-talkie) in order to share information about their teams and respective position; but that system is said to be unreliable as the devices have a range of coverage it can’t go beyond, and there are rarely monitoring centers that can help in case of warnings or emergencies.
FREQUENT ACCIDENT REASONSWe asked miners about the causation of frequent accidents in the underground mining, and they responded than mainly environmental hazards occurs more than manufacturing and human error accidents. Figure 2.1.Frequent accidents reasons As shown in the figure above, environmental hazards are the major cause of accidents in the underground, and it was said to occur mainly as season changes. For example in the rainy season when the soil gets wet, there is a high possibility of a landslide.Landslide: A collapse of a mass of earth or rock from a mountain or cliff.EXISTING SAFETY SYSTEMWe asked if there is any safety system in the underground mining that can warn them in case of accidents, and we got answers as follow; Figure 2.
2 Existing safety systemAs shown in the figure above, among all the interviewee, the majority replied negatively on the existence of safety system, as many of them said to have received training on occupational safety and health(OSH), where they get trained about using personal protective equipment(PPE) like headlamps and helmet. PROBLEM OF THE CURRENT COMMUNICATION SYSTEMAs this thesis focus on a proposal of a more reliable communication system in the mining environment in Rwanda, we asked about how reliable is the current communication model in the mines, and we got a shocking response as the majority of interviewee confirmed that many mining sites don’t use any communication from base to underground; others said that the system is unreliable as they use mobile phone which loses signal while in the underground, which can’t help in case of emergency. Figure 2.3.The problem of the current communication system Conclusion:Rwanda mining sector faces many challenges, But mostly miners are the one affected by the unwanted incident so far. According to the review and above analysis, there is no or unreliable safety system which is harmful to the mine workers that works in a hazardous environment.This research mainly focuses on introducing a communication system for a smooth functioning of mine workings and ensuring better safety. Proper and reliable communication systems not only save the machine breakdown time but also help in an immediate passing of messages from the vicinity of the underground working area to the surface for day-to-day normal mining operations as well as for speedy rescue operations in case of disaster CHAPTER 3: PREVIOUS STUDIESThe integration of different type of technology brought many changes in human lives in both developed and developing countries and the use of technology is increasing day by day.
Many communication Technologies have been introduced to mining and have increased the safety system. Recent research proves that wireless communication is more reliable than wired communication for the underground mining, and new technologies like wireless sensor networks are to be used in an actual mining environment. This research focuses on introducing an attribute-based communication system in the Rwandan mining environment which is a web system that will ease message delivery from between mineworkers and the surface base(monitoring room). There are some other proposed systems with the same concepts that are discussed in the following parts.WIRELESS COMMUNICATION IN UNDERGROUND MINESPersonal emergency device(Approved by DGMS, approval no. 629 of 2011 manufactured by Mine Site Technologies Pty. Ltd, Australia) The personal emergency device (PED) communication system is one-way TTE (inside the mine) system operating at a frequency range of 1 KHz for digital text messaging.
It is first demonstrated in the United States in 1990. The first successful evacuation of miners attributed to PED technology occurred during the Willow Creek Mine fire in Helper. Utah, on November 25, 1998(Helper, 1998). It is a portable device which utilizes Ultra Low Frequency (ULF) range for mine wide text messaging that propagates through rock strata.
It has been installed in over one hundred and fifty coal and metalliferous mines in Australia, USA, Canada, China, and Sweden. The PED system is an emergency warning system. PED stands for Personal Emergency Device. The use of ultra-low frequency (ULF) signals enables PED to transmit directly through rock strata, so wherever you are in a message can be sent to you. The mine wide signal coverage of PED also means it is a very useful day to day communication system.
Hence PED also stands for productivity Enhancement Device. Investment in a PED system is justified on significant cost savings and safety benefits. PED OperationsPED uses ultra-low frequency (ULF) signals to send signals directly through rock, so-called “through-the-earth” transmissions. The main difference between PED R and other so-called through-the-earth systems is that PED R is proven and is operating in many mines, 24 hours a day, 7 days a week. PED R has been installed in over 150 mines since 1990. The system has been refined and enhanced over this time, but the basic working principles remain the same.
The basic operation schematic is shown in the Figure below. The ULF transmission system transmits to a number of receiver types to allow a range of applications.Personal Receiver Personal Receiver is integrated with a miner’s cap lamp. This can be the ultra-lightweight lithium-ion battery pack, known as the Integrated Communications Cap Lamp (ICCL), or receiver versions are available to retrofit to some existing Cap lamp batteries (such as Koehler- Wheat, Oldham, Northern Lights and MSA). On receipt of a message, the cap lamp flashes, a buzzer sounds, and the 32 character text message are illuminated on a liquid crystal display. The PED R receivers always indicate that they and the transmission system are operating.
Figure 3.1 PED schematic operationThe result of this study in consideration of communication in an underground mining environment is that; PED is useful as it can allow us to transmit a message to the whole miners but an emergency situation, it might be important to submit different messages to miners according to their situation, and it is difficult to send such different messages in current communication (phone, email) because the sender have difficulty to know the situation of the whole receivers.ATTRIBUTE BASED COMMUNICATIONAttribute-based communications system include a set of communication units associated with a unique network identifier in a communication network having a switch, a registration center, and a registration database. Users establish user attribute records in the registration database for correlating attributes with a network identifier of the user communication unit. Users establish communication links between each other by referencing attributes of the target user rather than the network identifiers of the target user communication unit.
The system relates attribute based communication request messages with the registration database to derive the network identifiers for the communication units.In accordance with one illustrative embodiment of the present invention, there is provided a system that allows communications to occur on the basis of attributes rather than phone numbers. Attributes of people are one of the main drivers of communication. Currently, the requirement to know phone numbers restricts communication. By eliminating the need to know phone numbers an important barrier to communication is removed. Further, the same person can be reached on the basis of multiple attributes—thus providing multiple points on which a person can be reached.
CHAPTER 4: PROPOSED SOLUTIONIn the depths of a mine, communication is the key. Not knowing what your fellow miners are doing is dangerous enough from a miner’s viewpoint, but it can be even more dangerous if managers and foremen can’t communicate effectively with miners and other experts. Depending on the kind of mining being conducted, simply being in a mine can be extremely dangerous. Being in the wrong place at the wrong time can lead to disaster. While there are plenty of things that can happen in a mine that can’t be planned for, mines become much safer if care and preparation are put into proper communication channels.
But communication is the key to safety and success in mines, and those working with them need easy access to it. Many mines install communication systems that allow fast message delivery between the home base and the miners. Some systems use text messages to relay safety messages and inform others of hazards so that when disaster strikes, delays don’t cause unneeded deaths and injury. Mining accidents can happen in minutes, so each minute wasted could be the difference between life and death. These communication systems have the capability to send signals through the ground to miners and back to the control posts on the surface of the ground, a key technology that allows fast, reliable communication in mines.The proposed solution will deal with attribute based communication where the sender sends a message without necessarily knowing the receiver but by just tagging the message and the receiver or a group of receivers having the same tags can receive the message.Attribute-based communicationAn Attribute: in computing is a piece of information which determines the properties of a field or tag in a database or a string of characters in a display.
eg:Email,ID,Phone number,location,work position,etc.Attribute-based communications system: include a set of communication units associated with a unique network identifier in a communication network having a switch, a registration center, and a registration database. Figure 4.1: Proposed solution architectureAs shown in the figure above, Tags are used to specify the destination.
This concept helps us create a dynamical group of mineworkers for communication. Tags can be changed dynamically. (Ideally, the changing can be done by sensor information to reflect the miners’ situation to Tags.)Level 1Level 2Level 3Monitoring roomLevel 1Level 2Level 3Monitoring room Figure 4.2 Proposed message sending system ininterfaceFigure 4.2 describes the message sending illustration.
the Monitoring room will be using a web portal where they register every mineworker and assign them to attributes, in our case attributes used are the location of mineworkers in the underground(see figure 4.2) which is helpful in case of accidents to know locations of every mineworker on duty.The sending scenario has 3 steps:Step 1: mineworkers can pick their attribute manually or the tag can be assigned by the administrator,Step 2: the sender will write a message and attach the attribute before sending,Step 3: Receiver having the same attribute will receive the message.SYSTEM INTEGRATIONCommunication in the underground mine is a very complex technique that involves multidisciplinary subjects.
The proposed solution can not work itself as it requires internet connection and communication devices that are able to use the internet to receive messages and the underground mines in Rwanda do not have such infrastructure for our system to be installed.We focused on designing a communication system which when integrated with other systems can be used as a safety system for the mining environment. Figure 4.3 Safety system architectureFigure 4.3 describes a safety system which has three major parts:Data collection using a wireless sensor to collect information about the environmental aspects;Data analysis to perform information interpretation from sensors, assess the safety and generate warning messages if necessary;Data sharing or Data transportation which is our area of focus, to communicate the outcome and urge for evacuation if needed. CHAPTER 5: SYSTEM DESIGN AND DEVELOPMENTTo design a system we need to first state the requirement and proceed to the development.System design is the process of defining the components, modules, interfaces, and data for a system to satisfy specified requirements. System development is the process of creating or altering systems, along with the processes, practices, models, and methodologies used to develop them.
SYSTEM DESIGNThe proposed solution is a web-based system and in this part, we will define the requirements needed for the system to be developed.A web-based information system is an information system that uses Internet web technologies to deliver information and services, to users or other information systems/applications. Our system will use a client-server architecture.
Client-server architecture (client/server) is a network architecture in which each computer or process on the network is either a client or a server Figure 5.1 client-server architectureSYSTEM DEVELOPMENTThe system was developed using Python programming language which is an interpreted high-level programming language for general-purpose programming.Client: is a piece of computer hardware or software that accesses a service made available by a server. For web frontend, we used Bootstrap frontend framework which is a free and open-source front-end framework for designing websites and web applications.Server: a server is an instance of a computer program that accepts and responds to requests made by another program, known as a client.For the back end, we used Flask which is a micro web framework written in Python. It is classified as a microframework because it does not require particular tools or libraries.
Database: is a collection of information that is organized so that it can be easily accessed, managed and updated.For the database we used SQLite which is lite in times of memory and easy to use for prototyping purpose.SQLite: is an in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine.
The code for SQLite is in the public domain and is thus free for use for any purpose, commercial or private.This thesis main task after identifying communication as an issue in the Rwandan underground mining environment was to investigate on the data transfer part of the current communication used and come up with a suitable and more reliable solution.We investigated many possible solutions either wireless or wired communication, and finally came up with a proposal of attribute-based communication which is an already existing system, but our idea is to introduce it in the underground mining as a communication solution.In our context; we specified an attribute as a Tag which represents the destination of the message (i.e location of miners in the underground.)141033525069602324752584880 CLIENT SERVER 294349234584Get tag list00Get tag list1711960235585Tag assignment listTag assignment list790414205406333214112998Attach tag00Attach tag7439195875424797291824821797803245314UsersMessagesTags00UsersMessagesTags60443438993Send00Send51919486069Receive00Receive94539739574891206132607Figure 5.
2 Proposed web system design architectureAs shown in figure 5.2 The tagging is an essential part of our system as it describes the destination where the message has to be sent. Tags changes when the mineworkers change location in the underground. In that case, for now, the system administrator is the one who updates the tags manually; however, our initial idea was to have dynamical tags which means; Tags can be updated automatically by using thermal sensors but we couldn’t achieve the complete development of our idea.
Therefore we state that feature as a new challenge for future researchers interested in this field.CHAPTER 6: EXPERIMENTIn this chapter, we provide clear instructions and guidance on how end users can use the system.The system is a solution designed for mineworkers in Rwanda and the majority among them are technology illiterate, so we decided to simplify the system and make it more user-friendly.
The procedures before usage are as follow:All the mineworkers are registered by the system administrator in the database, and there is no other credentials involved rather than a username which can be one of the user’s name.Mineworkers are usernames are gathered into dynamic groups according to the location in the underground. For example, Mineworkers working in an area of 20 meters to 50 meters can be tagged as level 1.The steps to send a message to a particular tag are:Step 1: Input username;Step 2: Type the message in the message box;Step 3: Attach a tag referring to the message destination;Step 4: Click on the send button.-6896751976034Step 10Step 1-7749152665708Step 20Step 226967052890433003859077275869800-162732231699600-162732188304300367309825959662998922250297600697230206844274391917358104401519164433Step 4Step 42464231163453Step 3Step 3 Figure 6.1 web system interfaceThe steps to receive or check a message are :Step 1: Click on the inbox button;Step 2: Click on messages and read.-643180369979Step 1Step 2Step 1Step 2303082808580-223467984021RESULTSThe experiment was done by Five people; Three of who uses web system in their daily life and two specialists in web systems development.
We used four criteria of evaluation to measure the usability of our system and obtain some feedback.The results were overall good and a lot of new ideas were discussed for the system to be perfect.The four criteria are Effectiveness: Relates to the accuracy and completeness of the user to achieve his task;Efficiency: Relates to the level of effectiveness in performing the task;Satisfaction: Is the user comfort towards the use of the system;Overall system: Consists of both users, tasks, and equipment (hardware, software, and materials)EFFECTIVENESS EFFICIENCY SATISFACTION OVERALLBad 0 0 1 3Satisfactory 2 3 0 2Good 3 2 2 0Very good 0 0 3 0Total 5 5 5 5 Table 6.
1 Evaluation of the usability of the proposed solutionAs shown in Table 6.1 Satisfaction is high as mineworkers really need a reliable communication system to ensure their safety while in the underground but the overall is low because the environment and materials to use in our proposed solution like the internet are yet to be introduced in the Rwandan mining sector.Effectiveness and efficiency are not bad but we still need improvement. CHAPTER 7: CONCLUSIONIntroducing communication in the underground mines have many limitations as the type of communication systems used on the surface cannot be applied straightaway in underground mines due to high attenuation of radio waves in underground strata, besides the presence of inflammable gases and hazardous environment.
Nonsymmetric mine topology, uneven mine structure, complex geological structures, and extensive labyrinths put a further hindrance on the way of communication. Moreover, despite the Rwandan mining sector growing economically, technology is yet to be introduced mainly due to low literacy of mineworkers and low interest of mining companies in using technology that they claim to be expensive and not sure of its safety due to a hazardous environment. The government through its vision of introducing technology in all sectors in Rwanda is highly committed to introduce technology in the mining sector mainly for the safety of mineworkers and save the environment.For future researchers in this field we recommend the following:1. This proposed solution” attribute-based communication” is a reliable communication mainly for warning messages but it can work while integrated into a complete safety system composed by environment monitoring using wireless sensors and environment analysis using tools like”Thingspeak”;2.
This proposed solution has three main parts:Assign attributes;Send a message to attributes;Maintain attributes.The first two ones were covered in this research but to maintain the attributes in our case where attributes are defined by the location in the underground, we mean automatically update a new location in the system when a mineworker changes location.We believe that can be done using thermal sensors that detect body heat.REFERENCES1. Ranjan, A. and Sahu, H.B.
2014. “Communication Challenges in Underground Mines”, Search & Research, Vol. V, No.
(2), pp. 23-29, 2014. 2. http://rdb.rw/investment-opportunities/mining/#tab-1-33. International Journal of Engineering Trends and Technology(IJETT) – Volume 4 Issue 7 – July 2013,ISSN: 2231-5381 Page 3149 Wireless Communication Systems For Underground Mines – A Critical Appraisal Ashutosh Patri*1, Abhijit Nayak#2, Dr. S.
Jayanthu**3 *1B Tech Student, Mining Engg Department, #2B Tech Student, Computer Science Engg Department, **3Professor Mining Engg Department, National Institute of Technology, Rourkela, Odisha4. E-NEJAT: EARLY WARNING SYSTEM FOR MINER’S SAFETYBy NAJIBA HUSSAINI, HISATO SHIMA, KABERA MARIE GORETTI, NASRATULLAHGHAFOORI5. WIRELESS COMMUNICATION FOR UNDERGROUND MINES By Abhisek Maity Sem-VI, May-2015 Roll-D120061006-10844 Department of Mining Engineering Asansol Polytechnic Under Guidance of Prof. N.J.
Bhattacharjee Lecturer, Department of Mining Engineering Asansol Polytechnic6. https://patents.google.
com/patent/US200500325187. L. K. Bandyopadhyay, S. Kumar, P.
K. Mishra, A. Narayan and M. K. Sinha, “Studies on Wireless Communication systems for Underground Coal Mines”, Global Coal-2005, Int.
Seminar on Coal Science and Technology: Emerging Global Dimensions, pp. April 12-13, 2005, New Delhi. 8. A. Kumar, S. Chaulya, S. Kumar and L. K.
Bandyopadhyay, “Trapped miner detection, location and communication”, Minetech, Vol. 24 No. 6 pp. 1 – 13, 2003. 9. S.
Outalha, R. Le, and P. M. Tardif, Toward the unified and digital communication system for underground mines, CIM Bulletin, Vol. 93, pp.100-105, 2000.10. Underground Mine Communications, Control, and Monitoring, IC 8955, Bureau of Mines Information Circular, 1984.
11. S. Kumar, L. K.
Bandyopadhyay, A. Kumar and A. Narayan, “Improvised wireless communication system for underground coal mines utilizing active antenna,” Minetech, Vol. 24, No. 1, pp.
38 – 41, 2003. 12. Underground Mine Communications By JOHN N. MURPHY, SENIOR MEMBER, IEEE, AND J HOWARD E. PARKINSON 13. RADIO FREQUENCY COMMUNICATION SYSTEMS IN UNDERGROUND MINES By L.
K. Bandyopadhyay, P.K.
Mishra, Sudhir Kumar and A. Narayan Central Mining Research Institute, Barwa Road, Dhanbad- 826001, India. 14. THROUGH THE-EARTH ELECTROMAGNETIC TRAPPED MINER LOCATION SYSTEMS. A REVIEW By Walter E. Pittman, Jr., Ronald H. Church, and J.
T. McLendon Tuscaloosa Research center, Tuscaloosa, Ala.BUREAU OF UNITED STATES DEPARTMENT OF THE INTERIOR 15. Rescue and protection system for underground mine workers based on Zigbee By Tanmoy Maity, Assistant Professor, Department of Electrical Engineering Indian School of Mines, Dhanbad, India. Partha sarathi Das, Assistant Professor, Department of Electrical Engineering, Durgapur Institute of Advanced Technology and Management, Durgapur, INDIA and Mithu Mukherjee, Assistant Professor, Department of Electrical Engineering, Birbhum Institute of Engineering and Technology, Suri, WB, INDIA 16. Two-way Digital Wireless Telephonic Over High-Speed Infrastructure By Adcept Technologies Pvt. Ltd.
17. Mine Wide Communication System By Mine Site Technologies, Australia 18. WIRELESS COMMUNICATION IN U/G COAL MINES By RAKESH ROUSHAN 19. Mobile Radio Technology Magazine “A RAY OF LIGHT” Nov 1, 2007, 12:00 PM, By Mary Rose Roberts20. Modernization of Indian Coal Mining Industry: Vision 2025 By S.K.
Chauliya, L. K. Bandopadhyay, and P.K.
Mishra 21. Hybrid Wireless Communication System Using ZigBee and Wi-Fi Technology In The Coalmine Tunnels By Alfiya Shaikh Trinity College Of Engineering and Research, Pune. 22. RECENT TRENDS IN COMMUNICATION SYSTEMS FOR UNDERGROUND MINES By Dr. Singam Jayanthu* and Singam Jayadarshan** *Professor, Mining Engg Department, National Institute Of Technology, Rourkela- 563117** B Tech Student, Electronics and Communication Engg Dept, Sikkim Manipal Institute Of Technology- Sikkim, 737136 23. VERY LOW-FREQUENCY TECHNOLOGY AND ITS INTEGRATION INTO THE CONTEMPORARY RFID AND OTHER MINING SYSTEMS Valery A. Kononov Technical Solutions ( South Africa) Bernhard R.
Richter Selectronic Funk-und Sicherheitstechnik GmbH(Germany) 24. Client-server architecture HYPERLINK “https://www.webopedia.com/TERM/C/client_server_architecture.html” https://www.
webopedia.com/TERM/C/client_server_architecture.html25. A server in computing term HYPERLINK “https://www.computerhope.
com/jargon/s/server.htm” https://www.computerhope.com/jargon/s/server.htm26. HYPERLINK “https://en.wikipedia.
org/wiki/Flask_(web_framework)” https://en.wikipedia.org/wiki/Flask_(web_framework)27. HYPERLINK “https://en.wikipedia.
org/wiki/SQLite” https://en.wikipedia.org/wiki/SQLite28. Database connection – Wikipedia HYPERLINK “https://en.wikipedia.
org/wiki/Database_connection” https://en.wikipedia.org/wiki/Database_connection29. Bootstrap (front-end framework) https://en.wikipedia.org/wiki/Bootstrap_(front-end_framework)