মঙ্গলবার, ১২ ডিসেম্বর, ২০১৭

DATABASE MANAGEMENT SYSTEM (DBMS) Basic Concept:

DEFINITION :-
"A database management system is a collection of interrelated data and a set of programs to access those data. Collection of data is referred to as a database."
Primary goal of dbms is to provide a way to store and retrieve database information that is both convenient and efficient. Dbms allows us to define structure for storage of information and also provides mechanism to manipulate this information. Dbms also provides safety for the information stored despite system crashes or attempts of authorized access.

DATA ABSTRACTION :-
Major purpose of dbms is to provide users with abstract view of data i.e. the system hides certain details of how the data are stored and maintained. Since database system users are not computer trained, developers hide the complexity from users through 3 levels of abstraction, to simplify user’s interaction with the system.

1) Physical level of data abstraction :
This s the lowest level of abstraction which describes how data are actually stored.

2) Logical level of data abstraction :
This level hides what data are actually stored in the database and what relationship exists among them. 

3) View Level of data abstraction :
View provides security mechanism to prevent user from accessing certain parts of database.

SCHEMAS :-
1. The internal level has an internal schema, which describes the physical storage structure of the database. The internal schema uses a physical data model and describes the complete details of data storage and access paths for the database.

2. The conceptual level has a conceptual schema, which describes the structure of the whole database for a community of users. The conceptual schema hides the details of physical storage structures and concentrates on describing entities, data types, relationships, user operations, and constraints. A high-level data model or an implementation data model can be used at this level.

3. The external or view level includes a number of external schemas or user views. Each external schema describes the part of the database that a particular user group is interested in and hides the rest of the database from that user group. A high-level data model or an implementation data model can be used at this level.

4 TYPES OF DATABASE USERS :-
1) Naive users:
These are the unsophisticated users who interact with the system by invoking one of the application programs that have been written previously.
E.g. consider a user who checks for account balance information over the World Wide Web.

2) Application programmers:
These are computer professionals who write application programs, used to develop user interfaces. The application programmer uses Rapid Application Development (RAD) toolkit or special type of programming languages which include special features to facilitate generation of forms and display of date on screen.

3) Sophisticated users:
These users interact with the database using database query language. They submit their query to the query processor. Then Data Manipulation Language (DML) functions are performed on the database to retrieve the data. Tools used by these users are OLAP(Online Analytical Processing) and data mining tools.

4) Specialized users:
These users write specialized database applications to retrieve data. These applications can be used to retrieve data with complex data types e.g. graphics data and audio data.

ENTITY RELATIONSHIP MODEL :-
1. Entity :
• The basic object that the ER model represents is an entity, which is a "thing" in the real world with a independent existence.
• An entity may be an object with a physical existence—a particular person, car, house, or employee—or it may be an object with a conceptual existence—a company, a job, or a university course.

2. ATTRIBUTE :
• Each entity has attributes—the particular properties that describe it.
• For example, an employee entity may be described by the employee’s name, age, address, salary, and job.
• A particular entity will have a value for each of its attributes.
• The attribute values that describe each entity become a major part of the data stored in the database.
• Several types of attributes occur in the ER model: simple versus composite; single-valued versus multi-valued; and stored versus derived.

3. KEY :
• An important constraint on the entities of an entity type is the key or uniqueness constraint on attributes.
• A key is an attribute (also known as column or field) or a combination of attribute that is used to identify records.
• Sometimes we might have to retrieve data from more than one table, in those cases we require to join tables with the help of keys.
• The purpose of the key is to bind data together across tables without repeating all of the data in every table
• Such an attribute is called a key attribute, and its values can be used to identify each entity uniquely.
• For example, the Name attribute is a key of the COMPANY entity type because no two companies are allowed to have the same name.
• For the PERSON entity type, a typical key attribute is SocialSecurityNumber.
• Sometimes, several attributes together form a key, meaning that the combination of the attribute values must be distinct for each entity.
• If a set of attributes possesses this property, we can define a composite attribute that becomes a key attribute of the entity type.

- Types Of Keys :-
i) Super Key – An attribute or a combination of attribute that is used to identify the records uniquely is known as Super Key. A table can have many Super Keys.
ii) Candidate Key – It can be defined as minimal Super Key or irreducible Super Key. In other words an attribute or a combination of attribute that identifies the record uniquely but none of its proper subsets can identify the records uniquely.
iii) Primary Key – A Candidate Key that is used by the database designer for unique identification of each row in a table is known as Primary Key. A Primary Key can consist of one or more attributes of a table.
iv) Foreign Key – A foreign key is an attribute or combination of attribute in one base table that points to the candidate key (generally it is the primary key) of another table. The purpose of the foreign key is to ensure referential integrity of the data i.e. only values that are supposed to appear in the database are permitted.
v) Composite Key – If we use multiple attributes to create a Primary Key then that Primary Key is called Composite Key (also called a Compound Key or Concatenated Key).
vi) Alternate Key – Alternate Key can be any of the Candidate Keys except for the Primary Key.
vii) Secondary Key – The attributes that are not even the Super Key but can be still used for identification of records (not unique) are known as Secondary Key.

4. An E-R diagram can express the overall logical structure of a database graphically. E-R diagrams are simple and clear— qualities that may well account in large part for the widespread use of the E-R model. Such a diagram consists of the following major components:
• Rectangles, which represent entity sets
• Ellipses, which represent attributes
• Diamonds, which represent relationship sets
• Lines, which link attributes to entity sets and entity sets to relationship sets
• Double ellipses, which represent multi valued attributes
• Dashed ellipses, which denote derived attributes
• Double lines, which indicate total participation of an entity in a relationship set
• Double rectangles, which represent weak entity sets

RELATIONAL MODEL :-
The relational model represents the database as a collection of relations. Informally, each relation resembles a table of values or, to some extent, a "flat" file of records. When a relation is thought of as a table of values, each row in the table represents a collection of related data values. In the relational model, each row in the table
represents a fact that typically corresponds to a real world entity or relationship. The table name and column names are used to help in interpreting the meaning of the values in each row. In the formal relational model terminology, a row is called a tuple, a column header is called an attribute, and the table is called a relation. The
data type describing the types of values that can appear in each column is called a domain.

To preserve the consistency and correctness of its stored data, a relational DBMS typically imposes one or more data integrity constraints. These constraints restrict the data values that can be inserted into the database or created by a database update. Several different types of data integrity constraints are commonly found in relational databases, including:
 • Required data :
Some columns in a database must contain a valid data value in every row; they are not allowed to contain
missing or NULL values. In the sample database, every order must have an associated customer who placed the order. The DBMS can be asked to prevent NULL values in this column.

• Validity checking :
Every column in a database has a domain, a set of data values that are legal for that column. The DBMS can be
asked to prevent other data values in these columns.

• Entity integrity :
The primary key of a table must contain a unique value in each row, which is different from the values in all other
rows. Duplicate values are illegal, because they wouldn't allow the database to distinguish one entity from another. The DBMS can be asked to enforce this unique values constraint.

• Referential integrity :
A foreign key in a relational database links each row in the child table containing the foreign key to the row of the parent table containing the matching primary key value. The DBMS can be asked to enforce this foreign key/primary key constraint.

• Other data relationships :
The real-world situation modeled by a database will often have additional constraints that govern the legal data values that may appear in the database. The DBMS can be asked to check modifications to the tables to make sure that their values are constrained in this way.

• Business rules :
Updates to a database may be constrained by business rules governing the real-world transactions that are
represented by the updates.

• Consistency :
Many real-world transactions cause multiple updates to a database. The DBMS can be asked to enforce this
type of consistency rule or to support applications that implement such rules.

DATABASE LANGUAGES :-
  • Data definition language - defines data types and the relationships among them
  • Data manipulation language - performs tasks such as inserting, updating, or deleting data occurrences
  • Query language - allows searching for information and computing derived information
Advantages of DBMS :-
  1. Redundancy is controlled.
  2. Unauthorized access is restricted.
  3. Providing multiple user interfaces.
  4. Enforcing integrity constraints.
  5. Providing backup and recovery.
Disadvantages of File Processing System :-
  1. Data redundancy and inconsistency.
  2. Difficult in accessing data.
  3. Data isolation.
  4. Data integrity.
  5. Concurrent access is not possible.
  6. Security Problems.
Three levels of data abstraction :-
  1. Physical level: The lowest level of abstraction describes how data are stored.
  2. Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.
  3. View level: The highest level of abstraction describes only part of entire database.
Integrity Rules :-
There are two Integrity rules.
  • Entity Integrity : States that "Primary key cannot have NULL value".
  • Referential Integrity : States that "Foreign Key can be either a NULL value or should be Primary Key value of other relation.
NORMAL FORMS :-
  • 1 NF (Normal Form) :
The domain of attribute must include only atomic (simple, indivisible) values.
  • 2NF :
A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key.
  • 3NF :
A relation schema R is in 3NF if it is in 2NF and for every FD X A either of the following is true
  1. X is a Super-key of R.
  2. A is a prime attribute of R.
In other words, if every non prime attribute is non-transitively dependent on primary key.
  • 4NF :

A relation schema R is said to be in 4NF if for every Multivalued dependency X Y that holds over R, one of following is true.
1. X is subset or equal to (or) XY = R.
2. X is a super key.
  • What is 5NF :

A Relation schema R is said to be 5NF if for every join dependency {R1, R2, ..., Rn} that holds R, one the following is true
1. Ri = R for some i.
2. The join dependency is implied by the set of FD, over R in which the left side is key of R.

BCNF (Boyce-Codd Normal Form) :-
A relation schema R is in BCNF if it is in 3NF and satisfies an additional constraint that for every FD X A, X must be a candidate key.

Domain-Key Normal Form :-
A relation is said to be in DKNF if all constraints and dependencies that should hold on the the constraint can be enforced by simply enforcing the domain constraint and key constraint on the relation.

ACID Properties :-
ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably. In the context of databases, a single logical operation on the data is called a transaction. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction.
Jim Gray defined these properties of a reliable transaction system in the late 1970s and developed technologies to achieve them automatically. In 1983, Andreas Reuter and Theo Härder coined the acronym ACID to describe them.
  • Atomicity requires that each transaction is "all or nothing": if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged. An atomic system must guarantee atomicity in each and every situation, including power failures, errors, and crashes. To the outside world, a committed transaction appears (by its effects on the database) to be indivisible ("atomic"), and an aborted transaction does not happen.
  • The consistency property ensures that any transaction will bring the database from one valid state to another. Any data written to the database must be valid according to all defined rules, including but not limited to constraints, cascades, triggers, and any combination thereof. This does not guarantee correctness of the transaction in all ways the application programmer might have wanted (that is the responsibility of application-level code) but merely that any programming errors do not violate any defined rules.
  • The isolation property ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially, i.e. one after the other. Providing isolation is the main goal of concurrency control. Depending on concurrency control method, the effects of an incomplete transaction might not even be visible to another transaction.
  • Durability that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors. In a relational database, for instance, once a group of SQL statements execute, the results need to be stored permanently (even if the database crashes immediately thereafter). To defend against power loss, transactions (or their effects) must be recorded in a non-volatile memory.

বৃহস্পতিবার, ২৩ জুন, ২০১৬

A Project on Drone

A Project on Invention of Drone and It’s Multipurpose in our life with advantages and disadvantage

Definitions of Drone

 A drone, is a technological context, is an unmanned aircraft.
An unmanned aerial vehicle (UAV), commonly known as a drone. Essentially, a drone is a flying robot. The aircraft may be remotely controlled or can fly autonomously through software-controlled flight plans in their embedded systems working in conjunction with GPS. Drones are sometimes controlled by onboard computer systems. They can also be controlled with radio signals send by humans on the ground or in other aircrafts.

History of invention

In 1959, the U.S. Air Force, concerned about losing pilots over hostile territory, began planning for the use of unmanned aircraft.[13] Planning intensified after the Soviet Union shot down a U-2 in 1960. Within days, a highly classified UAV program started under the code name of "Red Wagon".[14] The August 1964 clash in the Tonkin Gulf between naval units of the U.S. and North Vietnamese Navy initiated America's highly classified UAVs (Ryan Model 147, Ryan AQM-91 Firefly, Lockheed D-21) into their first combat missions of the Vietnam War.[15] When the Chinese government [16] showed photographs of downed U.S. UAVs via Wide World Photos,[17] the official U.S. response was "no comment".
The War of Attrition (1967-1970) featured the introduction of UAVs with reconnaissance cameras into combat in the Middle East.
In the 1973 Yom Kippur War Israel used drones as decoys to spur opposing forces into wasting expensive anti-aircraft missiles.
 
In 1973 the U.S. military officially confirmed that they had been using UAVs in Southeast Asia (Vietnam).Over 5,000 U.S. airmen had been killed and over 1,000 more were missing or captured. The USAF 100th Strategic Reconnaissance Wing flew about 3,435 UAV missions during the war at a cost of about 554 UAVs lost to all causes. In the words of USAF General George S. Brown, Commander, Air Force Systems Command, in 1972, "The only reason we need (UAVs) is that we don't want to needlessly expend the man in the cockpit." Later that year, General John C. Meyer, Commander in Chief, Strategic Air Command, stated, "we let the drone do the high-risk flying ... the loss rate is high, but we are willing to risk more of them ... they save lives!
During the 1973 Yom Kippur War, Soviet-supplied surface-to-air missile batteries in Egypt and Syria caused heavy damage to Israeli fighter jets. As a result, Israel developed the first UAV with real-time surveillance. The images and radar decoys provided by these UAVs helped Israel to completely neutralize the Syrian air defenses at the start of the 1982 Lebanon War, resulting in no pilots downed. The first time UAVs were used as proof-of-concept of super-agility post-stall controlled flight in combat-flight simulations involved tailless, stealth technology-based, three-dimensional thrust vectoring flight control, jet-steering UAVs in Israel in 1987.
With the maturing and miniaturization of applicable technologies in the 1980s and 1990s, interest in UAVs grew within the higher echelons of the U.S. military. In the 1990s, the U.S. DoD gave a contract to AAI Corporation along with Israeli company Malat. The U.S. Navy bought the AAI Pioneer UAV that AAI and Malat developed jointly. Many of these UAVs saw service in the 1991 Gulf War. UAVs demonstrated the possibility of cheaper, more capable fighting machines, deployable without risk to aircrews. Initial generations primarily involved surveillance aircraft, but some carried armaments, such as the General Atomics MQ-1 Predator, that launched AGM-114 Hellfire air-to-ground missiles.
CAPECON was a European Union project to develop UAV's, running from 1 May 2002 to 31 December 2005.
As of 2012, the USAF employed 7,494 UAVs - almost one in three USAF aircraft. The Central Intelligence Agency also operated UAVs.
In 2013 at least 50 countries used UAVs. China, Iran, Israel and others designed and built their own varieties.
Drone Technology
Fig: Drone Technology
  
v  FPV (First Person View) Drone Technology
FPV means is “First Person View” which means a video camera is mounted on the unmanned aerial vehicle and broadcasts the live video to the pilot on the ground so the pilot is flying the aircraft as if he/she was on-board the aircraft instead of looking at the craft from the pilot’s actual ground position. FPV allows the unmanned aircraft to fly much higher and further than you can from the looking at the aircraft from the ground.  FPV control allows for more precise flying around obstacles especially with unmanned aerial vehicles which can easily fly indoors and through forests via FPV where you would not be able to see obstacles from a fixed position.
v  Flight Assistant Port
The flight control system communicates with a PC Assistant through a Micro-USB cable. This allows configuration of the UAV and upgrade the firmware.
v  UAV Remote Control System
This is the wireless communication device using the 5.8 GHz frequency band. The drone and the remote control system should already be paired when it leaves the factory.
v  Range Extender UAV Technology
This is a wireless communication device which operates within the 2.4 GHz frequency. It is used to extend the range of communication between a smart-phone and the drone in an open unobstructed area.  Transmission distance can reach up to 700 meters. Each range extender has a unique MAC address and network name (SSID).
v  Smartphone App Featuring Ground Station Function
Smartphone App from Google Play or the Apple Store . The app allows for full control of the drone. There is a specific feature called ground station function on the Phantom 2 Vision+ quad copter. This allows for flight missions by placing location waypoints and setting waypoint altitude and overall speed. The UAV should the be able to execute the flight mission automatically.

How Drones Work:

A typical unmanned aircraft is made of light composite materials to reduce weight and increase maneuverability. This composite material strength allows military drones to cruise at extremely high altitudes. Drones are equipped with different state of the art technology such as infra-red cameras(military UAV), GPS and laser (military UAV). Drones can be controlled by remote control system or a ground cockpit. Drones come in a wide variety of sizes, with the large drone mostly used for military purposes such as the Predator drone, other smaller drones which can be launched by hand, to other unmanned aircraft which require short runways. An unmanned aerial vehicle system has two parts, the drone itself and the control system.  
The nose of the unmanned aerial vehicle is where all the sensors and navigational systems are present. The rest of the body is complete innovation since there is no loss for space to accommodate humans and also light weight. The engineering materials used to build the drone are highly complex composites which can absorb vibration which decreases the noise produced.

The Drone and it’s multiple use in our Life

drone National scenari

Fig: National scenari

Drones have the potential to transform the world for the better. In the UK, the emergency services have started to use them to help people in danger, while the defence industry is exploring how drones can improve security.
Around the world, wildlife conservationists are embracing the technology to monitor animals and any potential threats against them by using drones.
European emergency services are being trained on how to use consumer drones in rescue operations and emergencies, including chemical spills, car accidents and widespread fires.
Ireland's Donegal Mountain Rescue Team has been using advanced drone software to help coordinate search and rescue missions in remote areas, while the Greater Copenhagen Fire Department in Denmark will be taught how to use drones to combat fires, chemical accidents and pile ups in both urban and over-water conditions.



 In medical sector
Ambulance drone
Ambulance drone

 A drone can save our life. Just like a “ambulance drone” . When it fly then it can, reducingcarry a medical toolbox and a oxygen mask. The ambulance drone can get a defibrillator to a patient within a 12 square kilometer (4.6 square miles) zone within a minute the chance of survival from 8 percent to 80 percent
streamline agriculture management
Agricultural drone
Agriculture management
Using a crop management system to observe, measure, and respond to variability in individual plants, farmers can target areas requiring attention. By pinpointing these areas, farmers can provide care only where needed—improving yield, conserving resources, and avoiding waste
Assisting with disasters
assisting with disasters of drone
 Assisting with disasters
Nothing strikes a strong nation more than a devastating natural disaster, when lives are lost, homes are lost and businesses are ruined for good. But drones have already been put to the test to assist with these sort of incidents, with the earthquake in Haiti being a great example. The US Government used drones to look for survivors and transport medication, protecting its troops from any danger.
Monitoring wildlife
Monitoring wildlife of Drone
Monitoring wildlife
Another useful thing we can do with drones is help protect Earth’s wildlife by monitoring it from afar, especially with endangered species. This has already been put to the test by a team of Indonesian scientists ,who have used drones to spy on a group of endangered apes, ensuring they are living well and are accessing the correct vegetation.

Deliveries
Delivering Drone
Delivering Drone
Amazon has showcased a prototype drone aimed at getting packages to its customers within 30 minutes.
The drone is part of Amazon's future delivery system known as Prime Air, where several different drones will be deployed for package deliveries.
The launch date remains unknown, but according to the new Prime Air micro site, the drones are being developed in the United States, the United Kingdom and Israel and being tested in "multiple international locations."
In 2013, Domino's released footage purporting to show tests of a remote-controlled pizza delivery and in 2014, a Russian pizza chain delivered by drone.
The rise of drone technology for deliveries raises the question of whether we will need to leave the house to go to the shops ever again
Inspecting oil rigs
Inspecting oil rigs
Inspecting oil rigs
Oil is a crucial resource, vital to the survival of many economies and mankind in general. Getting hold of it in the first place is generally dangerous, but don’t worry, as drones are already bein used  to make sure oil rigs are in tip-top condition and functioning as they ought to.

In war
 In war Drone
 In war Drone

This technology use for modern war. It helps us to war without soldier. The most obvious advantage of drones is that they greatly reduce putting military personnel in harm’s way or in combat.


to their size, unlike manned aircraft, drones are able to fly into areas that were once not possible. They can fly from only a few centimeters of the ground to 400 feet in the air as one long continuous shot, whilst panning and framing a chosen subject. Drones can fly from inside a room and out through a window or door, giving the aerial film makers a very unique shot. Furthermore, they can rotate on the same spot, move left, right up or down, all at the touch of the pilot’s command, whilst giving the camera operator total autonomy to position the camera to frame the perfect shot.


Full HD Quality
HD Quality photo us of Drone
HD Photo

Fig: Full HD Quality

As technology has improved, drones are still able to shoot in full HD and create amazing aerial videos, 4k and higher without sacrificing any quality. In fact, there are more and more gimbals (professional 3-axis stabilization systems) coming onto the market to accommodate the wide variety of cameras. This allows aerial filming companies to swap out the type of camera they wish to use, depending on the type of footage one is looking to capture.
3D maps

                                                                  Fig: 3D maps
Construction sites are utilizing them to present their work from a different perspective to prospective clients, as well as generating 3D maps. The drones are also able to generate maps from a series of photos that can then be run through software that will allow the user to measure distances or volumes without having to physically be on site.
Law enforcement


Fig:  Search
UAS can be used to search for lost children, provide tactical surveillance and suspect tracking, assist in accident  investigations and monitor large crowds.
Contribute to safe infrastructure maintenance and management
Fig: Risky place
Consider the difficulty of inspecting the underside of a bridge or the top of a skyscraper, not to mention the costs and risks. With UAS, scaffolding, cranes, or harnesses are not required. Just deploy the system to assess the structure's condition remotely
Network Rail
yah
Fig: Network Rail

Network Rail’s ORBIS project, which will see the railways in the UK digitised with 3D cameras and visualized online to analyze maintenance and field worker distribution. It currently uses aerial cameras but would like to use drones to get a better picture of the transport networks.

BBC and other British Media

  yah

Fig: BBC and other British Media

Media outlets like the BBC and Al Jazeera have begun using drones to film overhead – but with some undesirable consequences. Three BBC journalists were questioned after breaching high-level security protocols in Davos for the World Economic Forum, and Parisian police arrested three Al Jazeera reporters after their drone was spotted in the Boi de Boulogne skies.

Risky side of Drone in our life

Fig: Risky side of Drone
Drones also have the power to transform the world for the worse. While they have been used to protect against security threats, they have the capacity to be used as a deadly weapon.
 While still early days, the use of unmanned flying objects is set to change the world in which we live.
Some have also bemoaned the use of drones for spying and surveillance. But, as others have argued, does it really matter if you're not doing anything wrong?

Drone Traffic Regulations 
https://0.s3.envato.com/files/147788346/Large%20Group%20of%20Drones%20Flyng%20in%20Sky%20-%20IMAGE.jpg
Fig: Drone Traffic Regulations
Gone are the days of being able to fly a drone at will, even now, you have to follow the law of the land. Moving forward authorities will be turning their attention to drones specifically and the space will become increasingly regulated.




Drone Hijacking
http://www.diyphotography.net/wordpress/wp-content/uploads/2015/08/hackced-drone-670x300.jpg
Fig: Drone Hijacking
With Amazon and Dominoes looking at using Drones in their SCM cycle, it is feasible that soon there will be large amounts of goods being moved by drone. It’s only a matter of time before someone tries to hijack your drone for a free pizza or a free I pad.
The end of the “We have something for you” card 
http://www.worldinbeta.com/index.php/slir/w328/images/pullouts/DriverlessCARWIB.jpg
Fig: The end of the “We have something for you” card
With a drone’s ability to deliver day or night, at a time of your convenience, gone are the days of having to re-arrange a courier or visit your local Royal Mail depot with a “we have something for you” card.
Last mile disruption
 Last mile courier companies, who deliver from final transport hub to final destination, will be massively affected by drones, with short deliveries now made even easier by drones.
No more clear skies 
Our skies are no longer going to be empty wide spaces of blue or grey (in the case of London), they are going to be a chockablock ‘drone ways’.
Make room for drone stations 
http://i.dailymail.co.uk/i/pix/2014/05/05/article-2620944-1D96D2C800000578-719_634x449.jpg
Fig: drone stations 
With the widespread use of drones, we should expect the introduction of drone docking station in our cities and towns. These are places to for drones to refuel/recharge, as well as pick up and drop off goods.
Drone terrorism 
https://www.oodaloop.com/wp-content/uploads/2016/02/drone-bomb-750x375.jpg
Fig: Drone terrorism

 Cyber terrorism and crime is on the rise, and with more and more drones in the air, there is potential for these to be hijacked for terrorist use. The payload doesn’t even need to be explosive, fast and heavy flying objects can do enough damage by themselves. 
Drone economics 
The economics of drones is going to govern and affect a lot of decisions in the retail market. This will in turn have an impact on the price of commodities.
Drone throne 
A more light hearted possibility is the idea of drone wars and drone gaming, pitting drones against each other as a sport.
The applications and possibilities engendered by drones are endless, and merely limited by our own imagination. How do you think drones will impact society?
Employment 
http://vistaridge.ab.ca/wp-content/uploads/2015/12/nodronezone.jpg
Drones have the potential to supersede large amounts of courier roles, and there is the possibility that there will be many redundancies. Conversely there will be a need for more technically skilled people to manage and maintain an efficient drone delivery network. Whether the UK has the labor pool for this type of work is up for debate.
Deadly weapon
https://s-media-cache-ak0.pinimg.com/564x/92/f3/f7/92f3f77e8230dd67656ff665bada2203.jpg
Fig: Deadly weapon
Any weapon which can kill. This includes not only weapons which are intended to do harm like a gun or knife, but alsoblunt instruments like clubs, baseball bats, monkey wrenches, an automobile object which actually causes death.This becomes important when trying to prove criminal charges brought for assault with a deadly weapon. In a few 1990scases courts have found rocks and even penises of AIDS sufferers as "deadly weapons”.
Suicide Drones
https://i.ytimg.com/vi/5WGx_speFP0/maxresdefault.jpg
Fig: Suicide Drone
The first known use of a "suicide drone" is believed to have taken place during the recent fighting between Azerbaijan and Armenia.
Azerbaijani forces are thought to have deployed a drone tipped with explosives and crashed it into its target, rather than firing a missile. 
The drone slammed into a bus carrying Armenian volunteer soldiers and killed seven people, according to the Armenian defiance ministry.
Fighting periodically breaks out between Azerbaijan and Armenia over Nagorno-Karabakh, a self-declared Armenian republic that lies within the internationally recognized borders of Azerbaijan


Security threat
 The number of reported near-misses between drones and planes is on the rise. In the first four months of 2016, there were 15 reported near-misses, according to a Freedom of Information request.
Pilots have called for better safety regulation to prevent a collision as the risk remains "unacceptably high".
In April, a British Airways flight was hit by a suspected drone. Transport minister Robert Goodwill later admitted authorities had not yet confirmed whether what struck the Airbus A320 was a remote-controlled device - and that it may have actually been a plastic bag.
Although the aircraft landed intact and was later cleared for its next flight, it has renewed calls for more to be done to curb drone use
Passengers were terrified by a "huge bang" when the drone hit the rear carriage of the train on preserved railway tracks between Grosmont and Pickering. Luckily, in this case no damage or injuries were caused
Spying and monitoring
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Fig: Spying and monitoring
TV presenter Richard Madeley reported to the police two "peeping Toms" who were allegedly flying a drone over his garden to spy on him.
The former This Morning host, who was wearing just a pair of beach shorts at the time, said he gave chase to the "creeps" and located the suspected owners in a nearby white van, before contacting his local police force in Cornwall .
He told The Telegraph: "I would never dream of going out anywhere I might be photographed dressed like that – yet here, in my entirely private space, I was under surveillance, for who know’s what purpose. For me, this was a red line crossed."
The drone's owner ​has denied spying on Medley.
Drones are also being used by councils in England to fly over the homes of people seeking planning permission. A Freedom of Information survey of hundreds of councils found that a dozen had admitted to using or hiring drones.  Two councils said the drones could be used to check on planning applications.
The revelation raised questions over privacy.  The Liberal Democrats called for a code of practice to govern how councils use drones while the information watchdog said it was “concerned” by the  news and said councils should consider whether drones were “necessary and  proportionate”
   
               



 







Recommendation

Though drone has some disadvantages it is needed very badly in our modern life. So , research about drone should be increased.