Samsung

About: Samsung is a company organization based out in Seoul, South Korea. It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 134067 authors who have published 163691 publications receiving 2057505 citations. The organization is also known as: Samsung Group & Samsung chaebol.

A new PWM strategy for common mode voltage reduction in neutral-point clamped inverter-fed AC motor drives

Abstract: In this paper, the relationship between common-mode voltage and switching states in a neutral-point-clamped (NPC) inverter is clarified, and a new pulsewidth-modulation (PWM) strategy for reducing the common-mode voltage in an NPC inverter-fed AC motor drives is proposed. Among a total of 27 switching states in the NPC inverter, the proposed PWM uses only 19 switching states that generate common-mode voltage of which the magnitude is the same or less than one-sixth of DC-bus voltage. Moreover, the proposed PWM strategy satisfied the constraint that the output voltage vector should be changed by only one switching action. Not requiring extra hardware, the NPC inverter with the proposed PWM results in a remarkable reduction in peak-to-peak of common-mode voltage, compared to a two-level inverter and an NPC inverter controlled by conventional PWM. The proposed PWM strategy can be easily implemented in software without degradation of control performance in AC motor drives.

Micromachined piezoelectric membrane acoustic device

Abstract: This paper reports on a 3 mm ×3 mm ×0.003 mm piezoelectric membrane acoustic device, which works as a microphone and a microspeaker. It has a 0.5 μm thick zinc oxide (ZnO) piezoelectric thin film on a 1.5 μm thick low-stress silicon nitride membrane, made of LPCVD. The maximum deflection in the center of membrane, using laser Doppler vibrometer (LDV), is 1 μm at 7.3 kHz with input drive 15 V0-P (zero-peak). The output sound pressure level (SPL) of microspeaker is 76.3 dB SPL at 7.3 kHz, and 83.1 dB SPL at 13.3 kHz with input drive 15 V0-P. The distance between the reference microphone and piezoelectric microspeaker is 1 cm. The sensitivity of the microphone is 0.51 mV/Pa at 7.3 kHz with noise level of 18 dB SPL.

Custodian-based information sharing

Abstract: Information sharing systems such as iCloud, Dropbox, Facebook, and Twitter are ubiquitous today, but all of them depend on massive server infrastructure and always-on Internet connectivity. We have designed and implemented a sharing system that does not require infrastructure yet supports robust, distributed, secure sharing by opportunistically using any and all connectivity, local or global, permanent or transient, to communicate. One key element of this system is a new information routing model that so far has proven to be as scalable and efficient as the best of the current Internet routing protocols, while operating in an environment more complex and dynamic than they can tolerate. The new routing model is made possible by new affordances offered by information-centric networking, in particular, the open source CCN [1] release. This article describes the new system and its routing model, and provides some performance measurements.

Multilayered circuit type antenna package

Abstract: A multilayered antenna package including: a radio frequency integrated circuit (RFIC) interface layer that is configured to transmit a radio frequency (RF) signal; a first dielectric layer that is disposed on the RFIC interface layer; a coplanar waveguide layer that is disposed on the first dielectric layer and is configured to receive the RF signal transmitted by RFIC layer; a second dielectric layer disposed on the coplanar waveguide layer; and an antenna portion that is disposed on the second dielectric layer and is configured to irradiate a signal that is transmitted from the coplanar waveguide layer.

Echoes from the past: how technology mediated reflection improves well-being

Abstract: As people document more of their lives online, some recent systems are encouraging people to later revisit those recordings, a practice we're calling technology-mediated reflection (TMR). Since we know that unmediated reflection benefits psychological well-being, we explored whether and how TMR affects well-being. We built Echo, a smartphone application for recording everyday experiences and reflecting on them later. We conducted three system deployments with 44 users who generated over 12,000 recordings and reflections. We found that TMR improves well-being as assessed by four psychological metrics. By analyzing the content of these entries we discovered two mechanisms that explain this improvement. We also report benefits of very long-term TMR.