The Toyota Prius Transformed the Auto Industry

In the early 1990s, Toyota saw that environmental awareness and tighter emissions regulations would shape the future of the automotive industry. The company aimed to create an eco-friendly, efficient vehicle that would meet future standards.

In 1997 Toyota introduced the Prius to the Japanese market. The car was the world’s first mass-produced hybrid vehicle that combined gasoline and electric power to reduce fuel consumption and emissions. Its worldwide debut came in 2000.

Developing the Prius posed significant technical and market challenges that included designing an efficient hybrid power train, managing battery technology, and overcoming consumer skepticism about combining an electric drivetrain system with the standard gasoline-fueled power train. Toyota persevered, however, and its instincts proved prescient and transformative.

“The Prius is not only the world’s first mass-produced hybrid car, but its technical and commercial success also spurred other automakers to accelerate hybrid vehicle development,” says IEEE Member Nobuo Kawaguchi, a professor in the computational science and engineering department at Nagoya University’s Graduate School of Engineering, in Japan. He is also secretary of the IEEE Nagoya Section. “The Prius helped shape the role of hybrid cars in today’s automotive market.”

The Prius was honored with an IEEE Milestone on 30 October during a ceremony held at company headquarters in Toyota City, Japan.

The G21 project

The development of the Prius began in 1993 with the G21 project, which focused on fuel efficiency, low emissions, and affordability. According to a Toyota article detailing the project’s history, by 1997, Toyota engineers—including Takeshi Uchiyamada, who has since become known as the “father of the Prius”—were satisfied they had met the challenge of achieving all three goals.

The first-generation Prius featured a compact design with aerodynamic efficiency. Its groundbreaking hybrid system enabled smooth transitions between an electric motor powered by a nickel–metal hydride battery and an internal combustion engine fueled by gasoline.

The car’s design incorporated regenerative braking in the power-train arrangement to enhance the vehicle’s energy efficiency. Regenerative braking captures the kinetic energy typically lost as heat when conventional brake pads stop the wheels with friction. Instead, the electric motor switches over to generator mode so that the wheels drive the motor in reverse rather than the motor driving the wheels. Using the motor as a generator slows the car and converts the kinetic energy into an electrical charge routed to the battery to recharge it.

“The Prius is not only the world’s first mass-produced hybrid car, but its technical and commercial success also spurred other automakers to accelerate hybrid vehicle development.” —Nobuo Kawaguchi, IEEE Nagoya Section secretary

According to the company’s “Harnessing Efficiency: A Deep Dive Into Toyota’s Hybrid Technology” article, a breakthrough was the Hybrid Synergy Drive, a system that allows the Prius to operate in different modes—electric only, gasoline only, or a combination—depending on driving conditions.

A key component Toyota engineers developed from scratch was the power split device, a planetary gear system that allows smooth transitions between electric and gasoline power, permitting the engine and the motor to propel the vehicle in their respective optimal performance ranges. The arrangement helps optimize fuel economy and simplifies the drivetrain by making a traditional transmission unnecessary.

Setting fuel-efficiency records

Nearly 30 years after its commercial debut, the Prius remains an icon of environmental responsibility combined with technical innovation. It is still setting records for fuel efficiency. When in July 2023 the newly released 2024 Prius LE was driven from Los Angeles to New York City, it consumed a miserly 2.52 liters of gasoline per 100 kilometers during the 5,150-km cross-country journey. The record was set by a so-called hypermiler, a driver who practices advanced driving techniques aimed at optimizing fuel efficiency. Hypermilers accelerate smoothly and avoid hard braking. They let off the accelerator early so the car can coast to a gradual stop without applying the brakes, and they drive as often as possible at speeds between 72 and 105 km per hour, the velocities at which a car is typically most efficient.

A driver not employing such techniques still can expect fuel economy as high as 4.06 L per 100 km from the latest generation of Prius models.

Toyota has advanced the Prius’s hybrid technology with each generation, solidifying the car’s role as a leader in fuel efficiency and sustainability.

Milestone event attracts luminaries

Uchiyamada gave a brief talk at the IEEE Milestone event about the Prius’s development process and the challenges he faced as chief G21 engineer. Other notable attendees were Takeshi Uehara, president of Toyota’s power-train company; Toshio Fukuda, 2020 IEEE president; Isao Shirakawa, IEEE Japan Council history committee chair; and Jun Sato, IEEE Nagoya Section chair.

A plaque recognizing the technology is displayed at the entrance of the Toyota Technical Center, which is within walking distance of the company’s headquarters. It reads:

“In 1997 Toyota Motor Corporation developed the world’s first mass-produced hybrid vehicle, the Toyota Prius, which used both an internal combustion engine and two electric motors. This vehicle achieved revolutionary fuel efficiency by recovering and reusing energy previously lost while driving. Its success helped popularize hybrid vehicles internationally, advanced the technology essential for electric power trains, contributed to the reduction of CO2 emissions, and influenced the design of subsequent electrified vehicles.”

Administered by the IEEE History Center and supported by donors, the Milestone program recognizes outstanding technical developments worldwide. The IEEE Nagoya Section sponsored the nomination.

Reference: https://ift.tt/yKATdm3

Video Friday: Agile Upgrade

Video Friday is your weekly selection of awesome robotics videos, collected by your friends at IEEE Spectrum robotics. We also post a weekly calendar of upcoming robotics events for the next few months. Please send us your events for inclusion.

RoboCup German Open: 12–16 March 2025, NUREMBERG, GERMANY

German Robotics Conference: 13–15 March 2025, NUREMBERG, GERMANY

RoboSoft 2025: 23–26 April 2025, LAUSANNE, SWITZERLAND

ICUAS 2025: 14–17 May 2025, CHARLOTTE, NC

ICRA 2025: 19–23 May 2025, ATLANTA, GA

IEEE RCAR 2025: 1–6 June 2025, TOYAMA, JAPAN

RSS 2025: 21–25 June 2025, LOS ANGELES

IAS 2025: 30 June–4 July 2025, GENOA, ITALY

ICRES 2025: 3–4 July 2025, PORTO, PORTUGAL

IEEE World Haptics: 8–11 July 2025, SUWON, KOREA

IFAC Symposium on Robotics: 15–18 July 2025, PARIS

RoboCup 2025: 15–21 July 2025, BAHIA, BRAZIL

Enjoy today's videos!

Unitree rolls out frequent updates nearly every month. This time, we present to you the smoothest walking and humanoid running in the world. We hope you like it.]

[ Unitree ]

This is just lovely.

[ Mimus CNK ]

There’s a lot to like about Grain Weevil as an effective unitasking robot, but what I really appreciate here is that the control system is just a remote and a camera slapped onto the top of the bin.

[ Grain Weevil ]

This video, “Robot arm picking your groceries like a real person,” has taught me that I am not a real person.

[ Extend Robotics ]

A robot walking like a human walking like what humans think a robot walking like a robot walks like.

And that was my favorite sentence of the week.

[ Engineai ]

For us, robots are tools to simplify life. But they should look friendly too, right? That’s why we added motorized antennas to Reachy, so it can show simple emotions—without a full personality. Plus, they match those expressive eyes O_o!

[ Pollen Robotics ]

So a thing that I have come to understand about ships with sails (thanks, Jack Aubrey!) is that sailing in the direction that the wind is coming from can be tricky. Turns out that having a boat with two fronts and no back makes this a lot easier.

[ Paper ] from [ 2023 IEEE/ASME International Conference on Advanced Intelligent Mechatronics ] via [ IEEE Xplore ]

I’m Kento Kawaharazuka from JSK Robotics Laboratory at the University of Tokyo. I’m writing to introduce our human-mimetic binaural hearing system on the musculoskeletal humanoid Musashi. The robot can perform 3D sound source localization using a human-like outer ear structure and an FPGA-based hearing system embedded within it.

[ Paper ]

Thanks, Kento!

The third CYBATHLON took place in Zurich on 25-27 October 2024. The CYBATHLON is a competition for people with impairments using novel robotic technologies to perform activities of daily living. It was invented and initiated by Prof. Robert Riener at ETH Zurich, Switzerland. Races were held in eight disciplines including arm and leg prostheses, exoskeletons, powered wheelchairs, brain computer interfaces, robot assistance, vision assistance, and functional electrical stimulation bikes.

[ Cybathlon ]

Thanks, Robert!

If you’re going to work on robot dogs, I’m honestly not sure whether Purina would be the most or least appropriate place to do that.

[ Michigan Robotics ]

Reference: https://ift.tt/lAIqLHm

How Antivirus Software Has Changed With the Internet

We live in a world filled with computer viruses, and antivirus software is almost as old as the Internet itself: The first version of what would become McAfee antivirus came out in 1987—just four years after the Internet booted up. For many of us, antivirus software is an annoyance, taking up computer resources and generating opaque pop-ups.

But they are also necessary: Almost every computer today is protected by some kind of antivirus software, either built into the operating system or provided by a third party. Despite their ubiquity, however, not many people know how these antivirus tools are built.

Paul A. Gagniuc set out to fix this apparent oversight. A professor of bioinformatics and programming languages at the University Politehnica of Bucharest, he has been interested in viruses and antivirus software since he was a child. In his book Antivirus Engines: From Methods to Innovations, Design, and Applications, published last October, he dives deep into the technical details of malware and how to fight it, all motivated by his own experience of designing an antivirus engine—a piece of software that protects a computer from malware—from scratch in the mid-2000s.

IEEE Spectrum spoke with Gagniuc about his experience as a life-long computer native, antivirus basics and best practices, his view of how the world of malware and anti-virus software has changed over the last decades, the effects of cryptocurrencies, and his opinion on what the issues with fighting malware will be going forward.

How did you become interested in antivirus software?

Paul Gagniuc: Individuals of my age grew up with the Internet. When I was growing up, it was the wild wild West, and there were a lot of security problems. And the security field was at its very beginning, because nothing was controlled at the time. Even small children had access to very sophisticated pieces of software in open source. Knowing about malware provided a lot of power for a young man at that time, so I started to understand the codes that were available starting at the age of 12 or so. And a lot of codes were available.

I wrote a lot of versions of different viruses, and I did manage to make some of my own, but not with the intent of doing harm, but for self-defense. Around 2002 I started to think of different strategies to detect malware. And between 2006 and 2008 I started to develop an antivirus engine, called Scut Antivirus.

I tried to make a business based on this antivirus, however, the business side and programming side are two separate things. I was the programmer. I was the guy that made the software framework, but the business side wasn’t that great, because I didn’t know anything about business.

What was different about Scut Antivirus than the existing solution from a technical perspective?

Gagniuc: The speed, and the amount of resources it consumed. It was almost invisible to the user, unlike the antiviruses of the time. Many users at time started to avoid antiviruses for this reason, because at one point, the antivirus consumed so many resources that the user could not do their work.

How does antivirus software work?

Gagniuc: How can we detect a particular virus? Well, we take a little piece of the code from that virus, and we put that code inside an antivirus database.

But what do we do when we have 1 million, 2 million different malware files, which are all different? So what happens is that malware from two years, three years ago, for instance, is removed from the database, because that those files are not a danger to the community anymore, and what is kept in the database are just the new threats.

And, there’s an algorithm that’s described in my book called the Aho-Corasick algorithm. It’s a very special algorithm that allows one to check millions of viruses’ signatures against one suspected file. It was made in the 70s, and it is extremely fast.

“Once Bitcoin appeared, every type of malware out there transformed itself into ransomware.” —Paul Gagniuc, University Polytehnica of Bucharest

This is the basis of classical antivirus software. Now, people are using artificial intelligence to see how useful it can be, and I’m sure it can be, because at root the problem is pattern recognition.

But there are also malware files that can change their own code, called polymorphic malware, which are very hard to detect.

Where do you get a database of viruses to check for?

Gagniuc: When I was working on Scut Antivirus, I had some help from some hackers from Ukraine, who allowed me to have a big database, a big malware bank. It’s an archive which has several millions of infected files with different types of malware.

At that time, VirusTotal was becoming more and more known in in the security world. Before it was bought by Google [in 2012], VirusTotal was the place where all the security companies started to verify files. So if we had a suspected file, we uploaded to VirusTotal.

“I’m scared of a loss of know-how, and not only for antivirus, but for technology in general.” —Paul Gagniuc, University Polytehnica of Bucharest

This was a very interesting system, because it allowed for quick verification of a suspicious file. But this also had some consequences. What happened was that every security company started to believe what they see in the results of VirusTotal. So that did lead to a loss of diversity in the in different laboratories, from Kaspersky to Norton.

How has malware changed during the time you’ve been involved in the field?

Gagniuc: There are two different periods, namely the period up to 2009, and the period after that. The security world splits when Bitcoin appears.

Before Bitcoin, we had viruses, we had the Trojan horses, we had worms, we had different types of spiral key logs. We had everything. The diversity was high. Each of these types of malware had a specific purpose, but nothing was linked to the real life. Ransomware existed, but at the time it was mainly playful. Why? Because in order to have ransomware, you have to be able to oblige the user to pay you, and in order to pay, you have to make contact with a bank. And when you make the contact with a bank, you have to have an ID.

Once Bitcoin appeared, every type of malware out there transformed itself into ransomware. Once a user can pay by using Bitcoin or other cryptocurrency, then you don’t have any control over the identity of the hacker.

Where do you see the future of antiviruses going?

Gagniuc: It’s hard to say what the future will bring, but it’s indispensable. You cannot live without a security system. Antiviruses are here to stay. Of course, a lot of trials will be made by using artificial intelligence.

But I’m scared of a loss of know-how, and not only for antivirus, but for technology in general. In my view, something happened in the education of young people about 2008, where they became less apt in working with the assembler. Today, at my university in Bucharest, I see that every engineering student knows one thing and only one thing: Python. And Python uses a virtual machine, like Java, it’s a combination between what in the past was called a scripting language and a programming language. You cannot do with it what you could do with C++, for instance.

So at the worldwide level, there was a de-professionalization of young people, whereas in the past, in my time, everyone was advanced. You couldn’t work with a computer without being very advanced. Big leaders of our companies in this globalized system must take into consideration the possibility of loss of knowledge.

Did you write the book partially an effort to fix this lack of know-how?

Gagniuc: Yes. Basically, this loss of knowledge can be avoided if everybody brings their own experience into the publishing world. Because even if I don’t write that book for humans, although I’m sure that many humans are interested in the book, at least it will be known by artificial intelligence. That’s the reality.

Reference: https://ift.tt/AVmM1Sc

Home Microsoft 365 plans use Copilot AI features as pretext for a price hike

Microsoft has two announcements for subscribers to its Microsoft 365 Personal and Family plans today. First, you're getting the Copilot-powered AI features that Microsoft has been rolling out to businesses and Copilot Pro subscribers, like summarizing or generating text in Word, drafting slideshows in PowerPoint based on a handful of criteria, or analyzing data in Excel. Second, you'll be paying more for the privilege of using those features, to the tune of an extra $3 a month or $30 a year.

This raises the price of a Microsoft 365 Personal subscription from $6.99 a month or $69.99 a year to $9.99 and $99.99; a family subscription goes from $9.99 a month or $99.99 a year to $12.99 a month or $129.99 a year. For current subscribers, these prices go into effect the next time your plan renews.

Current subscribers are also being given an escape hatch "for a limited time." "Classic" Personal and Family plans at the old prices with no Copilot features included will still be offered, but you'll need to go to the "services & subscriptions" page of your Microsoft account and attempt to cancel your existing subscription to be offered the discounted pricing.

Read full article

Comments

Reference : https://ift.tt/6xCONEV

Microsoft patches Windows to eliminate Secure Boot bypass threat

For the past seven months—and likely longer—an industry-wide standard that protects Windows devices from firmware infections could be bypassed using a simple technique. On Tuesday, Microsoft finally patched the vulnerability. The status of Linux systems is still unclear.

Tracked as CVE-2024-7344, the vulnerability made it possible for attackers who had already gained privileged access to a device to run malicious firmware during bootup. These types of attacks can be particularly pernicious because infections hide inside the firmware that runs at an early stage, before even Windows or Linux has loaded. This strategic position allows the malware to evade defenses installed by the OS and gives it the ability to survive even after hard drives have been reformatted. From then on, the resulting "bootkit" controls the operating system start.

In place since 2012, Secure Boot is designed to prevent these types of attacks by creating a chain-of-trust linking each file that gets loaded. Each time a device boots, Secure Boot verifies that each firmware component is digitally signed before it’s allowed to run. It then checks the OS bootloader's digital signature to ensure that it's trusted by the Secure Boot policy and hasn't been tampered with. Secure Boot is built into the UEFI—short for Unified Extensible Firmware Interface—the successor to the BIOS that’s responsible for booting modern Windows and Linux devices.

Read full article

Comments

Reference : https://ift.tt/7oNvry3

Asimov's Laws of Robotics Need an Update for AI

In 1942, the legendary science fiction author Isaac Asimov introduced his Three Laws of Robotics in his short story “Runaround.” The laws were later popularized in his seminal story collection I, Robot.

• First Law: A robot may not injure a human being or, through inaction, allow a human being to come to harm.
• Second Law: A robot must obey orders given it by human beings except where such orders would conflict with the First Law.
• Third Law: A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

While drawn from works of fiction, these laws have shaped discussions of robot ethics for decades. And as AI systems—which can be considered virtual robots—have become more sophisticated and pervasive, some technologists have found Asimov’s framework useful for considering the potential safeguards needed for AI that interacts with humans.

But the existing three laws are not enough. Today, we are entering an era of unprecedented human-AI collaboration that Asimov could hardly have envisioned. The rapid advancement of generative AI capabilities, particularly in language and image generation, has created challenges beyond Asimov’s original concerns about physical harm and obedience.

Deepfakes, Misinformation, and Scams

The proliferation of AI-enabled deception is particularly concerning. According to the FBI’s 2024 Internet Crime Report, cybercrime involving digital manipulation and social engineering resulted in losses exceeding US $10.3 billion. The European Union Agency for Cybersecurity’s 2023 Threat Landscape specifically highlighted deepfakes—synthetic media that appears genuine—as an emerging threat to digital identity and trust.

Social media misinformation is spreading like wildfire. I studied it during the pandemic extensively and can only say that the proliferation of generative AI tools has made its detection increasingly difficult. To make matters worse, AI-generated articles are just as persuasive or even more persuasive than traditional propaganda, and using AI to create convincing content requires very little effort.

Deepfakes are on the rise throughout society. Botnets can use AI-generated text, speech, and video to create false perceptions of widespread support for any political issue. Bots are now capable of making and receiving phone calls while impersonating people. AI scam calls imitating familiar voices are increasingly common, and any day now, we can expect a boom in video call scams based on AI-rendered overlay avatars, allowing scammers to impersonate loved ones and target the most vulnerable populations. Anecdotally, my very own father was surprised when he saw a video of me speaking fluent Spanish, as he knew that I’m a proud beginner in this language (400 days strong on Duolingo!). Suffice it to say that the video was AI-edited.

Even more alarmingly, children and teenagers are forming emotional attachments to AI agents, and are sometimes unable to distinguish between interactions with real friends and bots online. Already, there have been suicides attributed to interactions with AI chatbots.

In his 2019 book Human Compatible, the eminent computer scientist Stuart Russell argues that AI systems’ ability to deceive humans represents a fundamental challenge to social trust. This concern is reflected in recent policy initiatives, most notably the European Union’s AI Act, which includes provisions requiring transparency in AI interactions and transparent disclosure of AI-generated content. In Asimov’s time, people couldn’t have imagined how artificial agents could use online communication tools and avatars to deceive humans.

Therefore, we must make an addition to Asimov’s laws.

• Fourth Law: A robot or AI must not deceive a human by impersonating a human being.

The Way Toward Trusted AI

We need clear boundaries. While human-AI collaboration can be constructive, AI deception undermines trust and leads to wasted time, emotional distress, and misuse of resources. Artificial agents must identify themselves to ensure our interactions with them are transparent and productive. AI-generated content should be clearly marked unless it has been significantly edited and adapted by a human.

Implementation of this Fourth Law would require:

• Mandatory AI disclosure in direct interactions,
• Clear labeling of AI-generated content,
• Technical standards for AI identification,
• Legal frameworks for enforcement,
• Educational initiatives to improve AI literacy.

Of course, all this is easier said than done. Enormous research efforts are already underway to find reliable ways to watermark or detect AI-generated text, audio, images, and videos. Creating the transparency I’m calling for is far from a solved problem.

But the future of human-AI collaboration depends on maintaining clear distinctions between human and artificial agents. As noted in the IEEE’s 2022 “Ethically Aligned Design“ framework, transparency in AI systems is fundamental to building public trust and ensuring the responsible development of artificial intelligence.

Asimov’s complex stories showed that even robots that tried to follow the rules often discovered the unintended consequences of their actions. Still, having AI systems that are trying to follow Asimov’s ethical guidelines would be a very good start.

Reference: https://ift.tt/8fN7vah

Be the Key Influencer in Your Career

This article is part of our exclusive career advice series in partnership with the IEEE Technology and Engineering Management Society.

When thinking about influencers, you might initially consider people with a large social media following who have the power to affect people with an interest in fashion, fitness, or food.

However, the people closest to you can influence the success you have in the early days of your career in ways that affect your professional journey. These influencers include you, your management, colleagues, and family.

Take control your career

You are—or should be—the most prominent influencer of your career. Fortunately, you’re the one you have the most control over.

Your ability to solve engineering problems is a significant determining factor in your career growth. The tech world is constantly evolving, so you need to stay on top of the latest developments in your specialization. You also should make it a priority to learn about related technical fields, as it can help you understand more and advance faster.

Another trait that can influence your career trajectory is your personality. How comfortable are you with facing awkward or difficult situations? What is your willingness to accept levels of risk when making commitments? What is your communication style with your peers and management? Do you prefer routine or challenging assignments? How interested are you in working with people from different backgrounds and cultures? Do you prefer to work on your own or as part of a team?

Most of those questions don’t have right or wrong answers, but how you respond to them can help you chart your path.

At the same time, be cognizant of the impression you make on others. How would you like them to think of you?

How you present yourself is important, and it’s within your control. Lead with confidence about your abilities, but don’t be afraid to seek help or ask questions to learn more. You want to be confident in yourself, but if you can’t ask for help or acknowledge when you’re wrong, you’ll struggle to form good relationships with your colleagues and management.

Learn about your company’s leadership

Your immediate supervisor, manager, and company leaders can impact your career. Much depends on your willingness to demonstrate initiative, accept challenging work, and be dedicated to the team.

Don’t forget that it is a job, however, and you will not stay in your first role forever.

Develop a good business relationship with your manager while recognizing the power dynamic. Learn to communicate with the manager; what works for one leader might not work for another. Like all of us, managers have their idiosyncrasies. Accept theirs and be aware of your own.

If your supervisor makes unachievable performance demands, don’t immediately consider it a red flag. Such stretch assignments can be growth opportunities, provided an environment of trust exists. But beware of bosses who become possessive and prevent you from accepting other opportunities within the organization rather than viewing you as the organization’s investment in talent.

Make it a priority to learn about your company’s leadership. How does the business work? What are the top priorities and values for the company, and why?

Find out the goals of the organization and your department. Learn how budgets are allocated and adjusted. Understand how the engineering and technology departments work with the marketing department, system integration, manufacturing, and other groups.

Companies differ in structure, business models, industry sectors, financial health, and many other aspects. The insight you gain from your managers is valuable to you, both in your current organization and with future employers.

Form strong relationships with coworkers

Take the time to understand your colleagues, who probably face similar issues. Try to learn something about the people you spend most of your day with attempting to solve technical problems. What do you have in common? How do your skills complement each other?

You also should develop social connections with your colleagues—which can enrich your after-work life and help you bond over job-related issues.

As a young professional, you might not fully understand the industry in which your employer operates. A strong collaborative relationship with more experienced colleagues can help you learn about customer needs, available products and services, competitors, market share, regulations, and technical standards.

By becoming more aware of your industry, you might even come up with ideas for new offerings and find ways to develop your skills.

Family ties are important

You’re responsible for your career, but the happiness and well-being of those close to you should be part of the calculus of your life. Individual circumstances related to family—a partner’s job, say, or parents’ health or children’s needs—can influence your professional decisions.

Your own health and career trajectory are also part of the whole. Remember: Your career is part of your life, not the entire thing. Find a way to balance your career, life, and family.

Planning your next steps

As engineers and technologists, our work is not just a means to earn a living but also a source of fulfillment, social connections, and intellectual challenge. Where would you like to be professionally in 5, 10, or 15 years? Do you see yourself as an expert in key technical areas leading large and impactful programs? A manager or senior executive? An entrepreneur?

If you haven’t articulated your objectives and preferences, that’s fine. You’re early in your career, and it’s normal to be figuring out what you want. But if so, you should think about what you need to learn before planning for your next steps.

Whatever your path forward, you can benefit from your career influencers—the people who challenge you, teach you, and cause you to think about what you want.

Reference: https://ift.tt/aBuOMvn