An approach to filling a data warehouse that employs bulk rewriting of the target data periodically is called refresh mode. Hence, option (d) will be considered relevant.
Give a brief account on data warehouse.A data warehouse, commonly referred to as an enterprise data warehouse (EDW), is a system used in computers for reporting and data analysis. It is seen to be a crucial component of business intelligence. DWs serve as central repository for data that has been combined from one or more sources. They centrally store both recent and historical data for the goal of providing analytical reports for staff members across the organization.
The warehouse stores the data that the operational systems upload (such as marketing or sales). Before being used in the DW for reporting, the data may go through an operational data storage and may need to be cleaned up for additional activities. ETL (extract, transform, load) and ELT (extract, load, transform) are the two primary methods used to construct a data warehouse system.
To know more about, data warehouse, visit :
https://brainly.com/question/14615286
#SPJ1
an organization has both windows and linux instances running and collecting log file information. what protocol will send the information to the centralized management information base (mib)?
SNMP send the information to the centralized management information base (MIB) for an organization has both windows and linux instances running and collecting log file information.
Network management makes extensive use of SNMP for network monitoring. In a management information base (MIB), which describes the status and configuration of the managed systems, SNMP provides management data in the form of variables.
Using SNMP, businesses can control and keep an eye on the devices connected to a LAN or WAN (WAN). The majority of commercially available network devices include SNMP agents. The agents can sometimes be installed by network administrators if not.
The Internet Architecture Board described the application layer protocol known as Simple Network Management Protocol in RFC 1157. To exchange management data between network devices, SNMP is employed. It is one of the protocols for network administration that is most frequently used. The Internet Engineering Task Force's definition of the Transmission Control Protocol/Internet Protocol (TCP/IP) suite includes SNMP.
To learn more about MIB click here:
brainly.com/question/15874187
#SPJ4
Cross-cultural team members might live in different time zones.
Members might send an email to other team members.
Email is a type of ________ communication.
O simoultaneous
O synchronous
O alternating
O asynchronous
Answer:
d. asynchronous
Explanation:
ben's system was infected by malicious code that modified the operating system to allow the malicious code author to gain access to his files. what type of exploit did this attacker engage in?
The attacker uses a backdoor approach because malicious malware that infected Ben's system changed the operating system to provide the malicious code author access to his data.
It circumvents all installed security mechanisms by employing any malware, virus, or technology to obtain unauthorized access to the application, system, or network. The method by which backdoor attacks enter the system determines how well they function.
This malware is a forgery that poses as another technology in order to carry out operations like data theft, malware installation, and opening a backdoor into the systems without being detected.
Due to its behavior resembling that of Trojans that allow an attacker to access the network's or software's fundamental infrastructure, it is also known as the "backdoor Trojan."
Consider it as a backdoor that property owners can utilize in an emergency. These backdoors are set up by experts in software or hardware, and they are not always malicious. They exist as a component of the software and permit owners/developers to gain instant access to the application/software.
To learn more about Operating system click here:
brainly.com/question/18095291
#SPJ4
which phase of the sdlc takes all the detailed design documents from the design phase and transforms them into the actual system?
The phase of the Systems Development Life Cycle (SDLC) that takes all the detailed design documents from the design phase and transforms them into the actual system is the Implementation phase.
Computer systems and software applications are developed and maintained using the SDLC process. It is broken down into a number of phases, each of which has a distinct goal and builds on what was accomplished in the phase before.
The design phase's extensive design documentation are translated into functional software or hardware during the implementation phase. Writing and testing code, creating and configuring hardware and software components, and integrating the various system components are all necessary steps in this process.
The system is constructed and tested during the implementation phase to make sure it satisfies the functional and technical specifications that were established during the earlier stages of the SDLC.
To know more about Systems Development Life Cycle (SDLC) kindly visit
https://brainly.com/question/28523436
#SPJ4
write a method swap that accepts an array of integers and two indexes and swaps the elements at those indexes
Here is an example of a Java method that accepts an array of integers and two indexes and swaps the elements at those indexes:
public void swap(int[] array, int index1, int index2) {
int temp = array[index1];
array[index1] = array[index2];
array[index2] = temp;
}
The input for this method is an array of numbers together with two indexes that indicate which components should be swapped. The value of the element at the first index is stored in a temporary variable before the element at the first index is given the value of the element at the second index. The swap is then finished by assigning the temporary variable's value, which contains the original value of the element at the first index, to the element at the second index.
To use this method, you would simply call it and pass in the array, the first index, and the second index as arguments. For example:
int[] array = {1, 2, 3, 4, 5};
swap(array, 1, 3);
This would swap the elements at indexes 1 and 3 in the array, resulting in an array of [1, 4, 3, 2, 5].
To know more about array of integers kindly visit
https://brainly.com/question/15048840
#SPJ4
which component of a file-sharing client intercepts requests for resources and determines if the resource is local or remote?
In a file-sharing client, the component that intercepts requests for resources and determines if the resource is local or remote is typically the client-side proxy.
A computer application known as a client-side proxy serves as a middleman between the client and the server. It takes client requests for resources, sends them to the server, and then gets the server's response and sends it back to the client.
The file sharing client-side proxy is in charge of intercepting requests for resources (such files or documents) in the context of file sharing and assessing whether the resource is stored locally on the client's workstation or if it needs to be fetched from a remote server. If the resource is locally saved, the proxy won't have to get in touch with the server to return it to the client.
If the resource is not locally available, the proxy will pass the file sharing client's request to the server, where the resource will be obtained.
An essential part of a file-sharing client, the client-side proxy lowers the number of requests that must be sent to the server and lowers the quantity of data that must be transmitted over the network, both of which contribute to the client's performance and efficiency.
To know more about file-sharing client kindly visit
https://brainly.com/question/17285463
#SPJ4
what property of virtualization allows entire virtual machines to be saved as file that can moved or copied like any other file?
Property of virtualization that allows entire virtual machines to be saved as file that can moved or copied like any other file is called encapsulation
What is encapsulation?Encapsulation refers to the idea of encapsulating data and the methods that operate on that data into a single entity, such as a Java class. This concept is also often used to hide the internal representation or state of an object from the outside world. This is called information hiding.
The general idea of this mechanism is simple. For example, some properties are not visible outside the object. Bind to methods that provide read or write access. Encapsulation allows you to hide certain information and control access to an object's internal state.
Lean more about encapsulation brainly.com/question/29107336
#SPJ4
by default, oracle commits each action query as soon as the user executes the query. a. true b. false
It is true that oracle commits each action query as soon as the user executes the query.
A group of data that is handled as a whole is called an Oracle database. A database's main function is to store and retrieve relevant data. The solution to information management's challenges is a database server. In a multiuser scenario, a server often manages a lot of data reliably so that multiple users can access the same material at once. Delivering excellent performance while accomplishing all of this. A Oracle database server also offers effective solutions for failure recovery and prevents illegal access.
The first database created for enterprise grid computing, the most adaptable and economical method of managing data and applications, is Oracle Database. Large pools of industry-standard, modular storage and servers are produced via enterprise grid computing.
Each new system can be quickly provisioned using this architecture's pool of components. Peak workloads are not required because it is simple to expand capacity or reallocate resources from resource pools as needed.
Both logical and physical structures can be found in the oracle database. Because the physical and logical structures are distinct, it is possible to control the physical storage of data without having an impact on how users can access logical storage structures.
To know more about Oracle kindly visit
https://brainly.com/question/14127109
#SPJ4
A company is experiencing overwhelming visits to a main web server. The it department is developing a plan to add a couple more web servers for load balancing and redundancy. Which requirement of information security is addressed by implementing the plan?.
C. availability. The availability is required for information security that is addressed by implementing the plan. Availability is one of part in the CIA triad.
The elements of CIA are confidentiality, Integrity, and Availability. CIA triad is the security model that is used to guide the security's organization. Confidentiality, integrity and availability, is called as the CIA triad, refers to a concept that is used to guide policies for information security within an organization. The model is sometimes pointed to as the AIC triad (availability, integrity and confidentiality) to avoid confusion with the Central Intelligence Agency. The Central Intelligence Agency (CIA) is a civilian foreign intelligence service of the federal government of the United States, tasked with gathering, processing, and analyzing national security information from around the world, primarily through the use of human intelligence (HUMINT).
The missing part in the question can be sen below:
A company is experiencing overwhelming visits to a main web server. The IT department is developing a plan to add a couple more web servers for load balancing and redundancy. Which requirement of information security is addressed by implementing the plan?
(A) integrity
(B) scalability
(C) availability
(D) confidentiality
Learn more about CIA triad, here https://brainly.com/question/13267367
#SPJ4
1. do some internet research to identify businesses who have suffered because of cloud security weaknesses or failures. what can companies who are contemplating cloud computing services learn from the negative experiences of these businesses? 2. do some internet research on security mechanisms associated with virtualization. how can virtualization be used by cloud service providers to protect subscriber data?
The standards for evaluating cloud workload security platforms from Forrester. Our distinct runtime protection, workflow integrations, entire lifecycle strategy, and unwavering commitment to the agent.
Why are businesses and some people worried about cloud computing?Many businesses have embraced cloud computing, but many lack the skills to make sure that it is being used securely by both themselves and their staff. Sensitive data is therefore at risk of disclosure, as seen by the enormous number of cloud data breaches.
What are the flaws in the public cloud platform's security? How can problems with cloud security be resolved?One frequent risk in cloud systems is identity and access management (IAM) which is not secure. In a word, it happens when a user of your infrastructure or service has access to resources they shouldn't and/or don't require.
to know more about Cloud security here:
brainly.com/question/28341875
#SPJ4
you're developing an application and want to focus on building, testing, and deploying. you don't want to worry about managing the underlying hardware or software. which cloud service type is best for you?
Platform as a service (PaaS) is the best cloud service type if you don't want to worry about managing the underlying hardware or software developing an application.
A full-featured cloud development and deployment environment called Platform as a Service (PaaS) includes all the tools you need to create anything from simple cloud-based apps to sophisticated business applications. You pay for the resources you require on a pay-as-you-go basis from a cloud service provider and access them over a secure Internet connection.
Along with infrastructure (servers, storage, and networking), PaaS also comprises middleware, development tools, business intelligence (BI) services, database management systems, and other things. PaaS provides support for all phases of a web application's lifecycle, including development, testing, deployment, management, and updating.
By adopting PaaS rather than buying and managing software licences, the infrastructure and middleware that support apps, container orchestrators like Kubernetes, development tools, and other resources, you can save money and time.
To learn more about cloud service type click here:
brainly.com/question/13485221
#SPJ4
you have just entered data into an online form. the box in which you entered the information is known as a
Online Form has fields like the text box, text area, drop-down menu, and radio button to establish areas on the page where the user can enter information.
The student should be able to do anything with the data once it has been entered. Information entered into form fields can be sent by email to the teacher, processed using a JavaScript or cgi-script application, printed, changed by an ASP page, or even visually compared by a student to a teacher-provided answer.
The foundation of web forms are form fields. They enable you to get data from respondents who complete your answer sheet. The majority of form creators have numerous field kinds where you may enter your title, objectives, and ask questions.
To learn more about Online form click here:
brainly.com/question/5871492
#SPJ4
advantages of firewire over USB cables
Answer:
firewire is faster
Explanation:
you can use ordinary cat3 telephone cables to connect a laptop to a router. choose the answer. question 1 options: true false
False. Ordinary cat3 telephone cables are not suitable for connecting a laptop to a router.
Cat3 cables, commonly referred to as Category 3 cables, are utilized in low-speed data networks and telephone systems. They are made to transfer voice and slow data over relatively short distances (up to 10 megabits per second) (up to 100 meters). High-speed data networks, like those used to link a laptop to a router, are not appropriate for their use.
You must use a cat3 cable or adapter that is compatible with both the network interfaces of the laptop and the router in order to connect a laptop to one. Depending on the kind of network connection being utilized, either an Ethernet cable or a wireless adaptor will normally be necessary for this. A connected connection is made between the laptop and the router using Ethernet connections.
To know more about Cat3 Cables kindly visit
https://brainly.com/question/4674056
#SPJ4
What happens if I don't patent my idea?
Someone will replicate your idea and sell it on the market if you don't copyright or patent it. As a result, there will be rivalry in the market. If they apply for a patent on the item, you might also lose your ability to compete with them.
Although patenting products requires time and money, the rewards are substantial. It is crucial that you obtain a patent for your idea, even if it is difficult for you to do so.
By preventing rival businesses from entering your particular area, having a patent portfolio will strengthen your market position. As a result, you will be in a superior position in the market with few competitors. As a result, your business will get a strong return on investment.
In the end, you might not be able to sell your idea. However, other people could have the means to commercialize your concept. Then, your business can receive licensing fees for utilizing your idea.
To learn more about Patent click here:
brainly.com/question/16137832
#SPJ4
what is the name of the windows cli utility that combines some of the attributes of both the ping and tracert commands over a period of time?
A route-tracing tool called Path Ping combines the functionality of Ping and Tracert with extra data that none of those tools provide.
What the ping and tracert commands over a period of time?At a command prompt, type ipconfig /all to check the IP address, subnet mask, and default gateway. Verify the DNS server's status as the authoritative one for the name being looked up. If so, see Looking for issues with reliable data.
The command traceroute pings each router hop on the way from the source to the destination and records the total time for each hop.
Therefore, Over a period of time, Path Ping transmits packets to every router on its path to the destination, and then computes results based on the packets received back from each hop.
Learn more about commands here:
https://brainly.com/question/18955190
#SPJ1
the branch of artificial intelligence that is concerned with building systems that incorporate the decision-making logic of a human expert is called:
The branch of artificial intelligence that is concerned with building systems that incorporate the decision-making logic of a human expert is called: expert systems.
Define artificial intelligence.
Unlike the intelligence exhibited by animals and humans, artificial intelligence is the ability of robots to perceive, synthesize, and infer information. The creation of public sector policies and legislation for developing and regulating artificial intelligence (AI) is referred to as artificial intelligence regulation (AI), and it is therefore connected to the more general regulation of algorithms.
The amount of data produced today, by both humans and machines, considerably exceeds the capacity of humans to comprehend, understand, and base complex decisions on that data. All computer learning is based on artificial intelligence, which is also the future of all complicated decision-making. For instance, even though there are 255,168 different ways to play tic-tac-toe, of which 46,080 result in a draw, most people can figure out how to avoid losing.
To learn more about artificial intelligence, use the link given
https://brainly.com/question/28448080
#SPJ4
arturo is installing a hardware server in the network room of a branch office. he wants to label it in a way that will be easy to differentiate it from other server machines but not clearly identify it should an unauthorized person gain physical access. how should he label it?
Before moving on to the next phase, the previous phase must be finished. Phases "trickle down" into one another until the application is developed, hence the phrase "waterfall" process.
The rigidity and structure of this methodology hindered the development of software. RUP (Rational Unified Process) offers a framework for segmenting software development into four gates. Inception, development, construction, and transition are the first three gates. The IBM-owned Rational Unified Process (RUP) approach offers a framework for segmenting software development into four "gates." The rigidity and structure of this methodology hindered the development of software.
Learn more about application here-
https://brainly.com/question/28206061
#SPJ4
What are the 8 key attributes?
For real-world things, a distinct attribute is frequently described in terms of their physical characteristics, such as size, form, weight, and color, etc.
Cyberspace objects may contain properties that describe their size, kind of encoding, network address, etc. A person's qualities or traits are referred to as personal attributes. This trait suggests something innate in them, like kindness, drive, and sensibility. Skills are distinct from attributes. In most cases, skills can be learned and developed through training. The results of the second study led to the development of a five-factor model of positive traits, including wisdom, harmony, joy, honesty, and tenacity.
Learn more about network here-
https://brainly.com/question/13992507
#SPJ4
Are patents based on a first to file basis?
Yes, patents are based on a first to file basis. This means that a patent is granted to the first person or entity who files a patent application with the U.S. Patent and Trademark Office (USPTO) for an invention. This is regardless of who was the first person or entity to invent the invention. In the United States, a patent application includes the description of the invention and a claim to the invention. The USPTO will then review the patent application and decide whether or not to grant the patent.
The first person who files a patent application for an invention is the one who will be granted the patent rights, regardless of who was the first to invent the product. Here is a step-by-step explanation of the process:
1. The inventor conceives of the invention and develops a prototype.
2. The inventor files a patent application with the relevant patent office.
3. The patent office reviews the application and decides whether the invention is novel, useful and non-obvious.
4. If the application is approved, the patent office will grant a patent to the inventor, giving them exclusive rights over their invention.
5. Once a patent is granted, it is the responsibility of the inventor to enforce their patent rights. This means that if someone else tries to make, use, or sell the invention without permission, the inventor can take legal action to stop them.
The current “first to invent” system is intended to award patents to the first person to invent a claimed invention—even if a later inventor beats the first inventor to the patent office.A patent is an exclusive right granted for an invention, which is a product or a process that provides, in general, a new way of doing something, or offers a new technical solution to a problem. To get a patent, technical information about the invention must be disclosed to the public in a application.
To learn more about PATENT Visit here : https://brainly.com/question/28943800
#SPJ4
another technician tells you that they are pxe booting a computer. what is the technician most likely doing with the computer? an in-place upgrade of the os installing an image to the computer over the network conducting a system repair using a multiboot configuration see all questions back skip question
The technician is most likely installing an image to the computer over the network. PXE (Preboot Execution Environment) booting allows a computer to boot up and load an operating system from a server on the network rather than from a local drive. This is often used to install images of operating systems, applications, and configuration settings on multiple computers at once.
The Benefits of PXE Booting for Installing Operating SystemsPXE (Preboot Execution Environment) booting is a powerful tool that allows computers to boot up from a server on the network, rather than from a local drive. This technology is often used to install images of operating systems, applications, and configuration settings on multiple computers at once. In this essay, the advantages of using PXE booting for installing operating systems will be discussed.
One of the main advantages of using PXE booting for installing operating systems is its speed and efficiency. By booting from the network, computers can be quickly set up with the latest version of the operating system instead of having to download and install the updates manually. Furthermore, PXE booting is much faster than using a USB drive to install the operating system, as the image is already on the server and can be accessed instantly.
Learn more about computers:
https://brainly.com/question/24540334
#SPJ4
write java code to test whether an integer n equals 10 and whether a floating-point number x is approximately equal to 10
Answer:
Here is Java code that tests whether an integer n equals 10, and whether a floating-point number x is approximately equal to 10.
// Test if an integer n equals 10
int n = 10;
if (n == 10) {
System.out.println("n equals 10");
} else {
System.out.println("n does not equal 10");
}
// Test if a floating-point number x is approximately equal to 10
double x = 9.99999;
if (Math.abs(x - 10) < 0.00001) {
System.out.println("x is approximately equal to 10");
} else {
System.out.println("x is not approximately equal to 10");
}
Explanation:
In this code, we first define an integer n and set it to 10. We then use an if statement to check if n equals 10. If it does, we print a message saying that n equals 10. Otherwise, we print a message saying that n does not equal 10.
Next, we define a floating-point number x and set it to a value that is close to 10. We then use another if statement to check if x is approximately equal to 10. To do this, we use the abs method from the Math class to calculate the absolute difference between x and 10, and check if it is less than a certain threshold (in this case, 0.00001). If the difference is less than the threshold, we print a message saying that x is approximately equal to 10. Otherwise, we print a message saying that x is not approximately equal to 10.
Overall, this code demonstrates two different ways to test whether a value is equal to or approximately equal to a given number. It can be useful in situations where you need to check if a value meets
Complete the sentence.
The _______ is the numbers of unique recordings made per second of an audio clip.
Recording short digital audio clips on a synthesizer allows musicians to recreate realistic sounds of musical instruments electronically. this is called Sampling.
What is Synthesizer?A synthesizer, sometimes known as a synthesizer, is a piece of electronic music that produces audio signals.Waveforms are generally produced by synthesizers using techniques including subtractive, additive, and frequency modulation synthesis to produce sounds.Filters, which cut or boost frequencies, envelopes, which regulate note articulation or how notes start and end, and low-frequency oscillators, which modulate parameters like pitch, volume, or filter characteristics affecting timbre, are some examples of components that can change the sound of these sounds.Synthesizers can be linked to other devices through MIDI and are frequently controlled by sequencers, software, or other instruments in addition to being performed with keyboards.Samples can be stacked, equalized, sped up or slowed down, re-pitched, looped, or otherwise modified. They can include elements like rhythm, melody, speech, sounds, or full bars of music. They are typically incorporated using either software, such as digital audio workstations, or hardware (samplers).
To learn more about audio clip refer to:
https://brainly.com/question/18440473
#SPJ1
How do I enlarge my screen?
To make everything on the screen bigger or smaller, hold down the CTRL keys while pressing both the + or - symbol.
Video display interfaces include monitors and displays. The simplest operational amplifier found in a standard software system, it. This can occasionally serve as an onscreen keyboard if it is converted together into multitouch display. Cathode ray tube (CRT) and liquid crystal display constitute two additional popular displays (LCD). Lcd displays most frequently used today are LCD panels.
The much more prevalent option of computer you can regularly find is LCD, followed by LED. LCD monitors have two glass panels with fluid between them and hundreds of row of sensors to manage the fluid.
To know more about MONITORS visit here :
https://brainly.com/question/11901631
#SPJ4
you need to stop an application from running in the task manager. which tab should you use to accomplish the task?
You need to stop an application from running in the task manager. Detail tab should you use to accomplish the task.
What is the 'Details' tab?
Game Analytics' 'Details' tab contains many statistics about the moves made in the game, as well as details about who won how and when the game was played. is also displayed. You can see the priority of each process on the Details tab.
Windows schedules process threads based on this ranking. However, you can do more on the Details tab and change the process priority.
What is the Details Tab in Salesforce?The Record Info Tabs component displays detailed record information, a list of related records, and a record feed.
Learn more about task manager:
brainly.com/question/6500846
#SPJ4
lipping: a. is a skin condition caused by aging. b. is a degenerative joint disease. c. is when bones develop indistinct and shaggy-appearing margins. d. is an endocrine disease caused by aging.
Answer:
c. is when bones develop indistinct and shaggy-appearing margins.
write the definition of the function add, that receives two integer parameters and returns their sum
Answer:
Here is the definition of the function add that receives two integer parameters and returns their sum:
def add(x, y):
return x + y
result = add(3, 5) # result will be 8
1. the process of checking data for validity and integrity before placing it in a data warehouse is called
Data cleansing is the process of validating and ensuring the integrity of data before storing it in a data warehouse. It is sometimes referred to as data cleaning or scrubbing, which is the process of locating and correcting mistakes, duplicates, and unnecessary data in a raw dataset.
Data cleansing is a step in the data preparation process that produces correct, tenable data that can be used to create trustworthy models, visualizations, and business choices.
This process of removing erroneous, damaged, badly structured, duplicate, or incomplete data from a dataset. When combining various data sources, there are several possibilities for data to be duplicated or improperly categorized. Even though results and algorithms seem to be accurate, faulty data renders them unreliable. There is no definite method to define the specific steps in the data cleaning process because the procedures will vary from dataset to dataset. But in order to ensure that you are performing your data cleaning operation correctly each time, it is crucial to building a template.
To learn more about data warehouse click here:
brainly.com/question/28249729
#SPJ4
a(n) system is a system that employs human knowledge, embedded in computer software, to solve problems that ordinarily require human expertise
An expert system is a system that employs human knowledge, embedded in computer software, to solve problems that ordinarily require human expertise.
Define an expert system.
An expert system is a computer program that simulates the judgment of a human expert in artificial intelligence. Expert systems, as opposed to typical procedural code, are created to reason through bodies of information that are primarily represented as if-then rules. An expert system is computer software that uses artificial intelligence (AI) techniques to replicate the decision-making and actions of a person or group with knowledge and experience in a certain field.
A knowledge-based information system that is built on artificial intelligence is known as a "business expert system" (BES).
To learn more about an expert system, use the link given
https://brainly.com/question/29485202
#SPJ4
. if the agent will only use the service for daytime calls, over what range of call minutes will each plan be optimal?
Plan A is optimal from zero to 197 minutes., Plan C is optimal from 197 minutes onward.
What is strategic capacity planning for products and services?
The overall objective of strategic capacity planning is to reach an optimal level where production capabilities meet demand. Capacity needs include equipment, space, and employee skills. If production capabilities are not meeting demand, it will result in higher costs, strains on resources, and possible customer loss.
What are the five steps of capacity planning?
Step 1: Check on the current SLA levels.
Step 2: Analyze your existing capacity.
Step 3: Determine your future needs.
Step 4: Identify any opportunities for consolidation.
Step 5: Make your capacity recommendations and take action.
Cost for Plan A: $89.60
Cost for Plan B: $101.80
Cost for Plan C: $95.00
Plan A is optimal from zero to 197 minutes.
Plan C is optimal from 197 minutes onward.
To know more about capacity planning:
https://brainly.com/question/13484626
#SPJ4