Contents

An Introduction

History of mobile operating systems

Latest mobile operating systems

Android

iOS (Apple)

Windows for mobile

BlackBerry OS

Bada (Samsung)

Symbian (Nokia)

Market comparison for the operating systems

Issues relating to the smart mobile phone operating

systems

Conclusion

Reference

CIITM/MBA/HR Page 1

Introduction

In present scenario mobile is an important and useful thing in

day to day life. This is the era of the smart-phones and plethora of

applications available for a particular smart phone. This is not the day

when phones are used only to make and receive calls or chatting with

friends via messaging. Today phones are not just a phone, these are

the smart phones which have all the features to pursue a smart life in

this rapidly growing age of technology. The people needs a technical

support on every go and the smart phones provide them all the

attributes like a personal computer.

The heart of a mobile device is its operating system, which

governs its built-in computing power as well as applications, services

like e-mail, and cellular-network features such as visual voice mail.

An operating system manages the hardware and software

resources of smart phones. Operating system creates an interface

between the user and the system. Some OS platforms cover the entire

range of the software stack. Others may only include the lower levels

(typically the kernel and middleware layers) and rely on additional

software platforms to provide a user interface framework. In mobile

systems it increase the productivity of the phone. This kind of mobile

phones in which operating systems are used are known as SMART

MOBILE PHONES. In this category we also include PDA’s, tables etc.

A Smart mobile OS reflects your lifestyle because it determines

the choice of apps and phone functionality. In mobile phones generally

Palm OS, BlackBerry, Windows for Mobile, Symbian, Android, and MAC

(iPhone OS) etc. operating systems are used which frequently update

with new features.

CIITM/MBA/HR Page 2

Before understanding operating system we have to know some

facts about smart phones.

*What are the smart phones?

Smart phones are usually thought of as being a mobile phone and a

handheld computer combined, but that does little to distinguish

between the vast number of different models on the market. So, before

we identify how to find the best smart phone for you, let's start by

splitting mobile phones into three categories that define what they're

capable of: dumbphones, featurephones, and smart phones.

First up is the dumbphone - not a very flattering description of the

technology that kick-started a global communications revolution, but

nonetheless fitting for phones that can do little more than make calls,

send text messages and manage your contacts.

Using a mobile phone as, well, a mobile phone is more than enough for

many people, but the rise of the internet has created a need for access

to other kinds of communication on the move. This is where the

featurephone comes in.

Although they work (and often look) just like a traditional mobile

phone, large colour screens and more powerful hardware mean that

featurephones are a bit more capable than dumbphones. Most can play

simple games, double up as a digital camera and act as a basic MP3

player, but web browsing and email are also on offer. Few

featurephones excel in any of these areas though, since they're

phones first and everything else second, so those extras are really only

suited to occasional use.

So, if you need all the power of an internet-connected computer

in your pocket, you need a smart phone. Qwerty keyboards, fast data

connections and the ability to install new applications mean that these

CIITM/MBA/HR Page 3

mini marvels can do almost anything a laptop can - albeit with a few

restrictions imposed by their smaller screens.

*What is mobile internet?

As far as smart phones are concerned, the mobile internet isn't

much different to the desktop internet. Unlike early featurephones that

relied on severely limited WAP browsers for web access, modern smart

phones have full web browsers that are every bit as capable as

Internet Explorer or Firefox.

Since screen sizes are closer to 4" than 14" though, browsing the web

on a smart phone does involve a few compromises. The most obvious

is that text can be too small to read until you zoom into a page, but

some smart phones make this so easy that the action soon becomes

second nature.

The best smart phones handle email just as easily as a desktop

or laptop computer, too. Almost all email service providers are

supported, which means you can manage your messages from

wherever you are.

Social networking works well with smart phones too, and having

access to Facebook or Twitter on a handheld device you always carry

with you makes such services all the more useful.

*What are the mobile applications?

Mobile applications - or 'apps' - are no different to the

applications you use on a desktop or laptop computer, and they're the

reason that the best touch screen phones are so powerful. Apps can

turn a smart phone into a powerful handheld games console, an ebook

reader, video player, sat-nav device and much more besides - and the

number of apps you can use is only limited by the storage capacity of

the smart phone.

CIITM/MBA/HR Page 4

Smart phone apps are downloaded from the internet using either

the smart phone itself, or with a computer for later installation via

synchronisation. There's a mix of free and paid-for apps for all smart

phone operating systems, but it's important to note that apps designed

for one won't work on another.

A wide selection of apps is no guarantee of quality, but it does

increase the chances of finding a particular app you want. The iPhone

is the smartphone currently favoured by many app creators and the

Apple App Store has thousands to download. Other smart phones don't

have anywhere near this number, so if there's a specific type of app

you know you'll want, find out if it's available for your chosen

smartphone before buying.

CIITM/MBA/HR Page 5

History

The first smartphone was the IBM simon; it was designed in 1992

and shown as a concept product that year at COMDEX, the computer

industry trade show held in Las Vegas, Nevada. It was released to the

public in 1993 and sold by BellSouth. Besides being a mobile phone, it

also contained a calendar, address book, world clock, calculator, note

pad, e-mail client, the ability to send and receive faxes, and games. It

had no physical buttons, instead customers used a touchscreen to

select telephone numbers with a finger or create faxes and memos

with an optional stylus. Text was entered with a unique on-screen

"predictive" keyboard. By today's standards, the Simon would be a

fairly low-end product, lacking a camera and the ability to download

third-party applications. However, its feature set at the time was highly

advanced.

The Nokia Communicator line was the first of Nokia's

smartphones starting with the Nokia 9000, released in 1996. This

distinctive palmtop computer style smartphone was the result of a

collaborative effort of an early successful and costly personal digital

assistant (PDA) by Hewlett-Packard combined with Nokia's best-selling

phone around that time, and early prototype models had the two

devices fixed via a hinge. The Communicators are characterized by

a clamshell design, with a feature phone display, keyboard and user

interface on top of the phone, and a physical QWERTY keyboard, high-

resolution display of at least 640×200 pixels and PDA user interface

under the flip-top. The software was based on the GEOS V3.0 operating

system, featuring email communication and text-based web browsing.

In 1998, it was followed by Nokia 9110, and in 2000 by Nokia 9110i,

with improved web browsing capability.

CIITM/MBA/HR Page 6

In 1997 the term 'smartphone' was used for the first time

when Ericsson unveiled the concept phone GS88, the first device

labelled as 'smartphone'.

CIITM/MBA/HR Page 7

The Android operating system for smart phones was released in

2008 in INDIA. It is an open-source operating system. Android OS

backed by Google, along with major hardware and software developers

(such as Intel, HTC, Motorola, Samsung, Nokia and many more).

Android OS is a modified version of Linux kernel. The Android SDK

includes debugger, libraries, a handset emulator, documentation,

sample code, and tutorials.

Google’s own participation in app development for Android platform

– These applications include Google Voice, Sky Map, Finance, Maps

Editor, Places Directory for their Local Search, Google Goggles that

searches by image, Google Translate, Listen for podcasts and My

Tracks.

Apart from these major OSs,there are many others that share smaller

markets, viz., Ubuntu, Maemo etc.

The Android operating system and the smart phones that run it

are seen as the main competitor to the iPhone, although nowhere near

as many have been sold. The Google Nexus One is considered to be

the definitive Android smart phone, but the HTC Desire is just as good.

Android isn't as polished as the iPhone operating system, but it looks

and works in a similar way - and the number of apps is quickly

growing.

CIITM/MBA/HR Page 8

Current features and specifications:

Handset layouts

The platform is adaptable to larger, VGA, 2D graphics library, 3D

graphics library based on OpenGL ES 2.0 specifications, and

traditional smartphone layouts.

Connectivity

Android supports connectivity technologies including GSM/EDGE,

IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, LTE,

NFC and WiMAX.

Supported applications

Now a days android has the biggest application market. It also

provide a no of applications with its hardware like text

messaging, Android Push Messaging service, web browser, media

player, video player, third-party applications and many more.

Additional hardware support

Android can use video/still cameras, touchscreens, GPS,

accelerometers, gyroscopes, barometers, magnetometers,

dedicated gaming controls, proximity and pressure sensors,

thermometers, accelerated 2D bit blits (with hardware

orientation, scaling, pixel format conversion) and accelerated 3D

graphics.

Multi-touch

Android has native support for multi-touch which was initially

made available in handsets such as the HTC Hero. The feature

was originally disabled at the kernel level (possibly to avoid

infringing Apple's patents on touch-screen technology at the

time). Google has since released an update for the Nexus

One and the Motorola Droid which enables multi-touch natively.

Multitasking

CIITM/MBA/HR Page 9

Multitasking of applications, with unique handling of memory

allocation, is available.

External storage

Most Android devices include microSD slot and can read microSD

cards formatted with FAT32, Ext3fs or Ext4fs file system. To

allow use of high-capacity storage media.

Android in a nutshell

Google's mobile operating system

Form factor: Available on all carriers, all shapes, all sizes

All capabilities: Range from budget to super premium

Not all Android phones are created equal in capability: some have

excellent cameras, screens, etc. Some don't.

Easiest compatibility with Google services, Google Music, other Android

devices

Interface: Varies by manufacturers, has a small learning curve for

some features

Key features: Free voice navigation with turn-by-turn directions, very

customizable, voice actions

Next big phone release: Samsung Galaxy Nexus phone

Next big operating system release: Android 4.0 Ice Cream Sandwich.

Released with Galaxy Nexus,

iOS (formerly iPhone OS) is a mobile operating system developed

and distributed by Apple Inc. Originally released in 2007 for

CIITM/MBA/HR Page 10

the iPhone and iTouch pad, it has since been extended to support

other Apple devices such as the ipad and Apple TV. Unlike Windows

CE (Mobile and Phone) and Android, Apple does not license iOS for

installation on non-Apple hardware.

The user interface of iOS is based on the concept of direct

manipulation, using multi-touch gestures. Interface control elements

consist of sliders, switches, and buttons. The response to user input is

immediate and provides a fluid interface. Interaction with the OS

includes gestures such as swipe, tap, pinch, and reverse pinch, all of

which have specific definitions within the context of the iOS operating

system and its multi-touch interface. Internal accelerometers are used

by some applications to respond to shaking the device or rotating it in

three dimensions. iOS is derived from Mac OS X, with which it shares

the Darwin foundation, and is therefore a Unix operating system.

In iOS, there are four abstraction layers: the Core OS layer,

the Core Services layer, the Media layer, and the Cocoa Touch layer.

Features & Specifications:

Home screen

The home screen also known as "SpringBoard",

displays application icons and a dock at the bottom of the screen

where users can pin their most frequently used apps. The home

screen appears whenever the user switches on the device or

presses the "Home" button.

Folder System

With iOS 4 came the introduction of a simple folder system. A

title for the folder is automatically selected by the type of

applications inside, but the name can also be edited by the user.

CIITM/MBA/HR Page 11

Notification Center

In the iOS 5, the notifications collate in a window which can be

dragged down from the top of the screen. If a user touches a

received notification, he/she will go to the application that sent

the notification.

Included applications

The iOS home screen contains these default "apps". All of the

utilities, such as voice memos, clock, calculator, and compass

are in one folder called "Utilities". Many of the included

applications are designed to share data. The iPod touch retains

the same applications that are present by default on the iPhone,

with the exception of the Phone, Messages, Compass and

Camera apps.

Multitasking

iOs supports multitasking through seven background applications

i.e. Background audio, Voice over IP, Background location, Push

notifications, Local notifications, Task completion & Fast app

switching.

Game Center

Game Center is an online multiplayer "social gaming network"

released by Apple. Through this user can play games online and

can also find and invite his / her friends to join and play the

games.

iPhone in a nutshell

Runs Apple's iOS 5 operating system

Available on three carriers: AT&T, Verizon, Sprint

Available on three storage sizes: 16GB, 32GB, 64GB

Easiest compatibility with iTunes, Apple ecosystem, and products

CIITM/MBA/HR Page 12

Form factor: One 3.5-inch screen (on the smaller size by today's

standards)

Interface: Approachable, but not very customizable. Some hidden

features

Key features: Excellent 8-megapixel camera, front-facing camera,

colorful Siri voice assistant

Next big release: iPhone 5

CIITM/MBA/HR Page 13

The current version is called “Windows Mobile 6.5″. It is based on

the Windows CE 5.2 kernel, and features a suite of basic applications

developed using the Microsoft Windows API. It is designed to be

somewhat similar to desktop versions of Windows, feature-wise and

aesthetically. Additionally, third-party software development is

available for Windows Mobile, and software can be purchased via the

Windows Marketplace for Mobile.

Third-party software development is available for the Windows

Phone operating system. There are several options for developers to

use when deploying a mobile application. This includes writing native

code with Visual C++, writing Managed code that works with the .NET

Compact Framework, or Server-side code that can be deployed using

Internet Explorer Mobile or a mobile client on the user’s device.

The .NET Compact Framework is actually a subset of the .NET

Framework and hence shares many components with software

development on desktop clients, application servers, and web servers.

Windows Mobile Professional runs on ‘Windows Phones’ with

touchscreens

Windows Mobile Standard runs on ‘Windows Phones’ with

regular screens

Windows Mobile Classic which runs on ‘Windows Mobile Classic

devices’

Features & Specifications :

CIITM/MBA/HR Page 14

Connectivity

Windows mobile phones provide connectivity with the world via

WiFi, 2G & 3G network connectivity. But window mobile phones

does not have Bluetooth because window having a problem of

generating viruses that’s why Bluetooth connectivity avoided

into window mobile phones.

Sensors

In window operating system powered mobile phones there are a

no of sensors available. In window phones proximity sensor,

multitouch sensor, motion sensor included for batter productivity

and usability of the mobile phones.

Application support

Window operating system market is not as large in compare to

the android and iOS. But it supports only genuine applications

from Microsoft site. There are a no. of inbuilt applications are

available with the window phones like messenger, media player,

video player, windows internet explorer web browser, camera

etc.

Microsoft office

Microsoft office is one of the unique feature of windows phones.

This is different from other smart phones. Windows operating

system powered mobile phones are basically pocket PC, coz

these have all the facilities like a personal computer.

Multitasking

As u all knows that windows is a multitasking operating system.

User can easily access more then one applications at a time.

Unlike others window has no limitations to access applications,

CIITM/MBA/HR Page 15

user can easily access seven – eight applications with the smart

phone at the time.

Windows Phone in a nutshell:

Microsoft's mobile operating system

Form factor: Available on all carriers, all shapes, all sizes.

AT&T has the largest and best selection

All capabilities: Mostly midrange, solid performers. Minimum 5-

megapixel camera

Easiest compatibility with Zune, Xbox Live, Microsoft services like

Microsoft Office, SkyDrive online storage

Interface: Very straightforward, but some hidden capabilities

Key features: Clean interface, built-in barcode-scanning and music

identification, Xbox Live integration, voice actions

Next big phone release: Nokia Lumia 800 or similar for U.S. markets

Next big operating system release: Unknown. Version 7.5 Mango

Proprietary software platform, created by Research In Motion, for

BlackBerry phones.

The operating system provides multitasking and supports

specialized input devices that have been adopted by RIM for use in its

handhelds, particularly the trackwheel, trackball, and most recently,

the trackpad and touchscreen.

The BlackBerry platform is perhaps best known for its native

support for corporate email, through MIDP 1.0 and, more recently, a

subset of MIDP 2.0, which and allows complete wireless activation and

CIITM/MBA/HR Page 16

synchronization with Microsoft Exchange, Lotus Domino, or Novell

GroupWise email, calendar, tasks, notes, and contacts, when used in

conjunction with BlackBerry Enterprise Server. The operating system

also supports WAP 1.2.

RIM’s BlackBerry OS has the most reliable email so BlackBerry

phones are considered the best email machines. It supports up to 10

private or corporate email accounts and instantly pushes messages to

your phone via RIM’s efficient servers. The OS also has the app store

called BlackBerry App World, a reliable browser, cool maps app, and

comprehensive media features. BlackBerry OS is menu-driven and

relies on a trackball or trackpad, but it also supports touch on devices

like the Storm. The OS integrates with Facebook (photo uploads, profile

pics, and more) and has an intelligent keyboard software called

SureType that, RIM fans say, turns average BlackBerry users into

typing machines.

Features and Specification :

Attractive qwerty hardware

Blackberry widely recognize as qwerty hardware. A large range

of mobile phone provided by blackberry are qwerty. These are

good in looking and loaded with special features.

Application support

As other operating systems blackberry also have its own market

for applications and at the same time it also comes with

preloaded applications.

BBM for blackberry

CIITM/MBA/HR Page 17

RIM operating system (Blackberry Operating System) have a very

unique feature that is BBM (BlackBerry Messenger). BBM create

messages with fun. When BBM activated on the device it makes

messaging and chatting very easy.

Connectivity

BlackBerry also known for its good connectivity supports. Every

device or mobile phone contain the features like wifi, Bluetooth,

edge etc.

Storage

BlackBerry does not have an external storage support. It comes

with inbuilt memory that is 8GB, 16GB, 32GB & 64GB.

BlackBerry Phone in a nutshell:

RIM (BlackBerry) mobile operating system

Form factor: Available with qwerty and touch models

Come out from the creativity of Research in motions

All capabilities: mid to high range, solid performers, good camera, BBM

Hardware oriented operating system

Interface: Very straightforward

Key features: Clean interface, connectivity, hardware

Next big phone release: Blackberry atom ver. 3.8

Next big operating system release: RIM 7.0

CIITM/MBA/HR Page 18

Made Open Source by contributions from Nokia, NTT DoCoMo, Sony

Ericsson and Symbian Ltd

Symbian has a microkernel architecture, which means that the

minimum necessary is within the kernel to maximize robustness,

availability and responsiveness. It contains a scheduler, memory

management and device drivers, but other services like networking,

telephony and filesystem support are placed in the OS Services Layer

or the Base Services Layer. The inclusion of device drivers means the

kernel is not a true microkernel. The EKA2 real-time kernel, which has

been termed a nanokernel, contains only the most basic primitives and

requires an extended kernel to implement any other abstractions. The

operating system consists of the kernel and middleware components of

the software stack. The upper layers are supplied by application

platforms like S60, UIQ, and MOAP.

Symbian, which powers most of Nokia’s phones, has been

shipped in more than 330 million devices worldwide. But in the last few

years, Symbian has seen more than its fair share of changes. In 2008,

Nokia, one of Symbian’s largest customers, acquired a major share in

the company. Nokia then created the Symbian Foundation to distribute

the platform as an open source project, and began the process of

opening up the source code that year.

Symbian’s move to open source has been completed four

months ahead of schedule and it offers mobile developers new ways to

innovate, says Williams. Any individual or organization can now take,

use and modify the Symbian code for any device, from mobile phone

to a tablet.

CIITM/MBA/HR Page 19

Features & Specification :

Connectivity

Symbian supports connectivity technologies

including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, and Wi-Fi,

Storage

Some of symbian operating system powered nokia mobile

phones does not have an external storage support. It comes with

inbuilt memory that is 8GB, 16GB, 32GB & 64GB. But as symbian

moving to the other company devices it comes with the facility of

external memory card slot.

Applications

Symbian providing a big application market for its powered

mobile operating systems and like other smart phones these

phones also contain some of preloaded applications like

messengers, web browsers, media players etc.

Sensors

Nokia providing a no. of sensors in its smart phones which are

powered by symbian mobile operating systems. These sensors

are proximity sensor, touch sensor, motion sensor and many

more.

Symbian in nutshell :

Firstly Nokia’s mobile operating system but now moving to other

mobile phones like sony ericsson, HTC etc.

Form factor: Available on all carriers, all shapes, all sizes

Capability: excellent cameras, screens, etc. Some don't.

Easiest compatibility with Google services, Google Music other

All capabilities: Range from budget to premium

Interface: Varies by manufacturers, has a small learning curve for

some features

Next big phone release: Sony Ericssion Ace 4

CIITM/MBA/HR Page 20

Next big operating system release

CIITM/MBA/HR Page 21

Developed by Samsung Electronics.

The Bada operating system has a kernel configurable

architecture, which allows the use of either the Linux kernel, or another

Real-time operating system (RTOS) kernel. The Linux kernel is the

preferred choice for smartphones, while RTOS is used for cheaper

feature-phones, due to its smaller memory footprint.

It has a web browser based on the open-source WebKit, and also

features Adobe Flash. Both WebKit and Flash can be embedded inside

native Bada applications. Bada offers interactive mapping with Point of

interest (POI) features, which can also be embedded inside native

applications.

Bada supports various sensors, such as motion sensing, vibration

control, face detection, accelerometer, magnetometer, tilt, and GPS,

which can be incorporated into applications. Native applications are

developed in C++ with the Bada SDK, and the Eclipse based IDE. Bada

can also run Java ME applications (MIDP profile).

Bada powered mobile operating systems comes with a large

display and high screen resolution that make the series of these type

of mobiles very popular.

Features & Specifications :

Hardware

Bada is an operating system which is owned by Samsung and it

contain a wide verity of smart phones like Wave series. These

comes in full touch screen facility and attractive designe.

CIITM/MBA/HR Page 22

Connectivity

Bada mobile phone operating system provides WiFi, Bluetooth,

Edge and JAVA support for batter connectivity. Bada also make

available its updates that keep user’s smart phone smart.

Applications

Samsung provide a market named samsung app that have a no.

of applications support to the bada operating system and the

phones also comes with a large no. of applications supported to

the particular cell phone.

Storage

All the smartphones which are powered by Bada have the

facility of attaching external card slot.

Features & specification :

Developed by Samsung electronics

Form factor: Available on all carriers, all shapes, all sizes

Capability: excellent cameras, screens, etc. Some don't.

Easiest compatibility with Google services

All capabilities: Range from budget to super premium

Interface: Varies by manufacturers, has a small learning curve for

some features

Next big phone release: Wave 4

Next big operating system release: bada 3.4

CIITM/MBA/HR Page 23

Market comparison for operating systems

As every one knows that mobile industry is rising day by day and

competition is increasing continuously. So every company trying to

occupy more and more market share for gaining a profit. In this race

the best rated operating systems gaining a good profit because of their

services.

Market comparison for the smart mobile phone operating

systems can be divided into two part – first one is market share of

sales and second one is market share of its popularity on the basis of

its applications and accessories.

Market share relating to the sales of mobile operating systems :

Here we have the data of sales for past four years.

YearAndroid (Google)

Blackberry (RIM)

IPhone (Apple)

badaSymbian (Nokia)

Windows Mobile/Phone (Microsoft)

2007 11.77 3.3 77.68 14.7

2008 23.15 11.42 11.26 72.93 16.5

2009 6.8 34.35 24.89 8.13 80.88 15.03

2010 67.22 47.45 46.6 11.76 111.58 12.38

As the data shown that how much the market is increasing day by day. The data are showing that symbian was leading the market till 2010 but resent data says that iOS is the leading operating system in today’s market.

CIITM/MBA/HR Page 24

Graphically these data are shown below :

These data are of February 2011

These data are of February 2012

CIITM/MBA/HR Page 25

Market share of applications associated with these operating systems

CIITM/MBA/HR Page 26

Conclusion

According to the study in respect of smart mobile phone

operating systems and the comparison there on, the conclusion is

stated below-

Firstly user goes on the attractive looks of device and most of the

users prefer android smart phones because these phones are available

with high resolution touch screen display, good speakers, music and

video players, games and many other applications. These smart

phones having excellent cameras.

As per as the processor gives the speed to smart mobile phones,

iOS (apple) comes at first, followed by android, blackberry, symbian,

windows for mobile and bada.

Study focuses a shiny light on the connectivity of the smart

mobile phones. Now a day user prefer the smart phones loaded with

WiFi facility, Bluetooth connectivity, edge and many more connectivity

features that’s why user goes to iOS or blackberry followed by

android, symbian, bada and windows mobiles.

As the study concluded that the iOS that is designed for apple

hardware comes into the super premium range, windows, blackberry,

symban, bada and android comes into affordable to super premium

range. Android make the user to choose its own choice from a wide

range of smart handsets from affordable to super premium range.

CIITM/MBA/HR Page 27

Issues relating to the smart mobile phone operating systems

As we all knows that every technology have some of the drawbacks and issues relating with it. Same as here is also some issues associated with this smart mobile phones operating systems. These issues are as follows.

Security

Mobile phone operating systems are not as secure so that every user trusted on smart phones.

Privacy

Some of the operating systems not provide the privacy relating to the data that may be of

Affordability

CIITM/MBA/HR Page 28

CIITM/MBA/HR Page 29

Submitted By :Meenakshi

JangidMBA II sem.

Compucome Institute of information Technology &

Managemenet

Submitted To :Jasmeet Sigh

SMART MOBILE PHONE OPERATING SYSTEMS