Jin and Ming - an Intergenerational Study of the Roles of Women in East Asia

This thesis discusses some of the current dilemmas faced by women in East Asia. Women from different life backgrounds may make different choices when faced with life paths, but whether they choose to pursue a career or return to the family, there are potential pitfalls and no easy paths left for them. In the first part, the paper explores gender issues from a global perspective, the road to gender equality for women in Asian countries lags far behind that of the Nordic countries and has a long way to go. This thesis then analyses the situation from within the East Asian countries themselves and discusses the historical and social reasons for this situation. In the following section, some examples of the three East Asian countries are specifically expanded. In the past decade, China, Japan and South Korea have sparked a huge debate on gender issues. On the one hand, some traditional concepts of patriarchal society are gradually disintegrating in such a change, and on the other hand, the women themselves are under great pressure and suffering from this change. The road ahead of them is not an easy one, but it is a necessary one for women\u27s liberation

On One-way Functions and Kolmogorov Complexity

We prove that the equivalence of two fundamental problems in the theory of computing. For every polynomial $t(n)\geq (1+\varepsilon)n, \varepsilon>0$, the following are equivalent: - One-way functions exists (which in turn is equivalent to the existence of secure private-key encryption schemes, digital signatures, pseudorandom generators, pseudorandom functions, commitment schemes, and more); - $t$-time bounded Kolmogorov Complexity, $K^t$, is mildly hard-on-average (i.e., there exists a polynomial $p(n)>0$ such that no PPT algorithm can compute $K^t$, for more than a $1-\frac{1}{p(n)}$ fraction of $n$-bit strings). In doing so, we present the first natural, and well-studied, computational problem characterizing the feasibility of the central private-key primitives and protocols in Cryptography

Adaptation in Standard CMOS Processes with Floating Gate Structures and Techniques

We apply adaptation into ordinary circuits and systems to achieve high performance, high quality results. Mismatch in manufactured VLSI devices has been the main limiting factor in quality for many analog and mixed-signal designs. Traditional compensation methods are generally costly. A few examples include enlarging the device size, averaging signals, and trimming with laser. By applying floating gate adaptation to standard CMOS circuits, we demonstrate here that we are able to trim CMOS comparator offset to a precision of 0.7mV, reduce CMOS image sensor fixed-pattern noise power by a factor of 100, and achieve 5.8 effective number of bits (ENOB) in a 6-bit flash analog-to-digital converter (ADC) operating at 750MHz. The adaptive circuits generally exhibit special features in addition to an improved performance. These special features are generally beyond the capabilities of traditional CMOS design approaches and they open exciting opportunities in novel circuit designs. Specifically, the adaptive comparator has the ability to store an accurate arbitrary offset, the image sensor can be set up to memorize previously captured scenes like a human retina, and the ADC can be configured to adapt to the incoming analog signal distribution and perform an efficient signal conversion that minimizes distortion and maximizes output entropy

Comprehensive evaluation of window-integrated semi-transparent PV for building daylight performance

© 2019 Elsevier Ltd Building-integrated semi-transparent photovoltaic windows (PV windows) have been considered as a potential candidate to replace conventional windows to improve building energy efficiency and hence reduce carbon emissions. With the integration of PV windows, the indoor luminous environment may be significantly affected. The presence of solar cells may cause undesirable shading, low illuminance levels and affect colour quality of the transmitted daylight. Therefore, it is important to comprehensively assess daylight performance of PV windows to ensure a comfortable luminous environment. In this study, the daylight performance of Cadmium telluride (CdTe) PV window with four different transparencies (i.e. 20%, 30%, 40% and 50%) applied to a cellular office space has been assessed in terms of daylight quantity and daylight quality. RADIANCE was selected to predict the annual daylight performance through advanced dynamic metrics including Useful Daylight Illuminance (UDI), simplified Daylight Glare Probability (DGPs) and Illuminance Uniformity (Uo). Correlated Colour Temperature (CCT) and Colour Rendering Index (CRI), which are two attributes to characterise the colour quality of transmitted daylight were used to evaluate performance of the selected PV windows. CCT and CRI were calculated under three CIE standard daylight scenarios (CCT of 4000 K, 6500 K and 25000 K respectively). It is found that CdTe PV windows can significantly improve the homogeneity of daylight distribution on a task area located close to the window and reduce the risk of daylight glare when compared with the performance of a conventional double glazing. Moreover, the recommended CCT (i.e. 3000–7500 K) can be achieved with the employment of CdTe PV windows under 4000 K and 6500 K daylight scenarios. All of the CdTe PV windows examined were able to maintain CRI at a comfortable level i.e. above 90 under the three daylight scenarios

Cryptography from Sublinear-Time Average-Case Hardness of Time-Bounded Kolmogorov Complexity

Let \mktp[s] be the set of strings $x$ such that $K^t(x) \leq s(|x|)$, where $K^t(x)$ denotes the $t$-bounded Kolmogorov complexity of the truthtable described by $x$. Our main theorem shows that for an appropriate notion of mild average-case hardness, for every $\varepsilon>0$, polynomial $t(n) \geq (1+\varepsilon)n$, and every ``nice\u27\u27 class \F of super-polynomial functions, the following are equivalent: - the existence of some function T \in \F such that $T$-hard one-way functions (OWF) exists (with non-uniform security); - the existence of some function T \in \F such that \mktp[T^{-1}] is mildly average-case hard with respect to sublinear-time non-uniform algorithms (with running-time $n^{\delta}$ for some $0<\delta<1$). For instance, existence of subexponentially-hard (resp. quasi-polynomially-hard) OWFs is equivalent to mild average-case hardness of \mktp[\poly\log n] (resp. \mktp[2^{O(\sqrt{\log n})})]) w.r.t. sublinear-time non-uniform algorithms. We additionally note that if we want to deduce $T$-hard OWFs where security holds w.r.t. uniform $T$-time probabilistic attackers (i.e., uniformly-secure OWFs), it suffices to assume sublinear time hardness of \mktp w.r.t. uniform probabilistic sublinear-time attackers. We complement this result by proving lower bounds that come surprisingly close to what is required to unconditionally deduce the existence of (uniformly-secure) OWFs: \mktp[\poly\log n] is worst-case hard w.r.t. uniform probabilistic sublinear-time algorithms, and \mktp[n-\log n] is mildly average-case hard for all $O(t(n)/n^3)$-time deterministic algorithms

A Direct PRF Construction from Kolmogorov Complexity

While classic result in the 1980s establish that one-way functions (OWFs) imply the existence of pseudorandom generators (PRGs) which in turn imply pseudorandom functions (PRFs), the constructions (most notably the one from OWFs to PRGs) is complicated and inefficient. Consequently, researchers have developed alternative \emph{direct} constructions of PRFs from various different concrete hardness assumptions. In this work, we continue this thread of work and demonstrate the first direct constructions of PRFs from average-case hardness of the time-bounded Kolmogorov complexity problem \mktp[s], where given a threshold, $s(\cdot)$, and a polynomial time-bound, $t(\cdot)$, \mktp[s] denotes the language consisting of strings $x$ with $t$-bounded Kolmogorov complexity, $K^t(x)$, bounded by $s(|x|)$. In more detail, we demonstrate a direct PRF construction with quasi-polynomial security from mild average-case of hardness of \mktp[2^{O(\sqrt{\log n})}] w.r.t the uniform distribution. We note that by earlier results, this assumption is known to be equivalent to the existence of quasi-polynomially secure OWFs; as such, our results yield the first direct (quasi-polynomially secure) PRF constructions from a natural hardness assumptions that also is known to be implied by (quasi-polynomially secure) PRFs. Perhaps surprisingly, we show how to make use of the Nisan-Wigderson PRG construction to get a cryptographic, as opposed to a complexity-theoretic, PRG

On One-way Functions and Sparse Languages

We show equivalence between the existence of one-way functions and the existence of a \emph{sparse} language that is hard-on-average w.r.t. some efficiently samplable ``high-entropy\u27\u27 distribution. In more detail, the following are equivalent: - The existence of a $S(\cdot)$-sparse language $L$ that is hard-on-average with respect to some samplable distribution with Shannon entropy $h(\cdot)$ such that $h(n)-\log(S(n)) \geq 4\log n$; - The existence of a $S(\cdot)$-sparse language L \in \NP, that is hard-on-average with respect to some samplable distribution with Shannon entropy $h(\cdot)$ such that $h(n)-\log(S(n)) \geq n/3$; - The existence of one-way functions. Our results are inspired by, and generalize, the recent elegant paper by Ilango, Ren and Santhanam (ECCC\u2721), which presents similar characterizations for concrete sparse languages

One-way Functions and Hardness of (Probabilistic) Time-Bounded Kolmogorov Complexity w.r.t. Samplable Distributions

Consider the recently introduced notion of \emph{probabilistic time-bounded Kolmogorov Complexity}, pK^t (Goldberg et al, CCC\u2722), and let MpK^tP denote the language of pairs (x,k) such that pK^t(x) \leq k. We show the equivalence of the following: - MpK^{poly}P is (mildly) hard-on-average w.r.t. \emph{any} samplable distribution D; - MpK^{poly}P is (mildly) hard-on-average w.r.t. the \emph{uniform} distribution; - Existence of one-way functions. As far as we know, this yields the first natural class of problems where hardness with respect to any samplable distribution is equivalent to hardness with respect to the uniform distribution. Under standard derandomization assumptions, we can show the same result also w.r.t. the standard notion of time-bounded Kolmogorov complexity, K^t

On One-way Functions and the Worst-case Hardness of Time-Bounded Kolmogorov Complexity

Whether one-way functions (OWF) exist is arguably the most important problem in Cryptography, and beyond. While lots of candidate constructions of one-way functions are known, and recently also problems whose average-case hardness characterize the existence of OWFs have been demonstrated, the question of whether there exists some \emph{worst-case hard problem} that characterizes the existence of one-way functions has remained open since their introduction in 1976. In this work, we present the first ``OWF-complete\u27\u27 promise problem---a promise problem whose worst-case hardness w.r.t. \BPP (resp. \Ppoly) is \emph{equivalent} to the existence of OWFs secure against \PPT (resp. \nuPPT) algorithms. The problem is a variant of the Minimum Time-bounded Kolmogorov Complexity problem (\mktp[s] with a threshold $s$), where we condition on instances having small ``computational depth\u27\u27. We furthermore show that depending on the choice of the threshold $s$, this problem characterizes either ``standard\u27\u27 (polynomially-hard) OWFs, or quasi polynomially- or subexponentially-hard OWFs. Additionally, when the threshold is sufficiently small (e.g., $2^{O(\sqrt{n})}$ or \poly\log n) then \emph{sublinear} hardness of this problem suffices to characterize quasi-polynomial/sub-exponential OWFs. While our constructions are black-box, our analysis is \emph{non- black box}; we additionally demonstrate that fully black-box constructions of OWF from the worst-case hardness of this problem are impossible. We finally show that, under Rudich\u27s conjecture, and standard derandomization assumptions, our problem is not inside \coAM; as such, it yields the first candidate problem believed to be outside of \AM \cap \coAM, or even ${\bf SZK}$, whose worst case hardness implies the existence of OWFs